Abstract: A power MOSFET 100 has a source metal 112 that contacts silicided source regions 114 through vias 160 etched in an insulating layer 200. The silicide layer 225 provides for a relatively small but highly conductive contact and thus reduces RDSON. The insulating material may be any suitable material including and not limited to one or a combination of materials such as BPSG, PSG, silicon dioxide and silicon nitride. The insulating layer is relatively thin and does not extend deeply into the gate trench, thereby reducing capacitance.

Abstract: A process for fabricating vertical CMOS devices, featuring variable channel lengths, has been developed. Channel region openings are defined in composite insulator stacks, with the channel length of specific devices determined by the thickness of the composite insulator stack. Selective removal of specific components of the composite insulator stack, in a specific region, allows the depth of the channel openings to be varied. A subsequent epitaxial silicon growth procedure fills the variable depth channel openings, providing the variable length, channel regions for the vertical CMOS devices.

Abstract: A semiconductor device is disclosed, which includes a semiconductor substrate, drain and source regions of a MOS transistor, a gate electrode formed on a surface of a channel region of the MOS transistor trench type element isolation regions in each of which an insulating film is formed on a surface of a trench formed in the surface of the semiconductor substrate, the element isolation regions sandwiching the channel region from opposite sides thereof in a channel width direction, and a conductive material layer for a back gate electrode, which is embedded in a trench of at least one of the element isolation regions, configured to be supplied with a predetermined voltage to make an depletion layer in a region of the semiconductor substrate under the channel region of the MOS transistor or to voltage-control the semiconductor substrate region.

Abstract: A dual gate transistor device and method for fabricating the same. First, a doped substrate is prepared with a patterned oxide layer on the doped substrate defining a channel. Next, a silicon layer is deposited to form the channel, with a gate oxide layer then grown adjacent the channel. Subsequently, a plurality of gate electrodes are formed next to the gate oxide layer and a drain is formed on the channel. After the drain is formed, an ILD layer is deposited. This ILD layer is etched to form a source region contact, a drain region contact, a first gate electrode contact, and a second gate electrode contact.

Abstract: A semiconductor device constituting an IGBT exhibits low losses yet can be manufactured using an inexpensive wafer and with high yields, and exhibits low losses. The IGBT is produced by using a wafer, for example an FZ wafer, that is cut form an ingot and has its surface polished and cleaned, wherein an n-type impurity diffusion layer having an enough dose to stop the electric field in turn-off is provided between a collector layer and a base layer as a field-stop layer for stopping an electric field in turn-off. The thickness of this field-stop layer defined by Xfs−Xj is controlled in the range from 0.5 &mgr;m to 3 &mgr;m, where Xfs is the position at which the impurity concentration in the field-stop layer is twice the impurity concentration of the base layer, and Xj is the position of the junction between the filed-stopping layer and the collector layer.

Abstract: A power MOSFET has a plurality of spaced rows of parallel coextensive trenches. The trenches are lined with a gate oxide and are filled with a single common layer of conductive polysilicon which extends into each trench and overlies the silicon surface which connects adjacent trenches. The source contact is made at a location remote from the trenches and between the rows of trenches. The trenches are 1.8 microns deep, are 0.6 microns wide and are spaced by about 0.6 microns or greater. The trench is from 0.2 to 0.25 microns deeper than the channel region. The device has a very low figure of merit and is useful especially in low voltage circuits.

Abstract: A gate dielectric containing LaAlO3 and method of fabricating a gate dielectric contained LaAlO3 produce a reliable gate dielectric having a thinner equivalent oxide thickness than attainable using SiO2. The LaAlO3 gate dielectrics formed are thermodynamically stable such that these gate dielectrics will have minimal reactions with a silicon substrate or other structures during processing. A LaAlO3 gate dielectric is formed by evaporating Al2O3 at a given rate, evaporating La2O3 at another rate, and controlling the two rates to provide an amorphous film containing LaAlO3 on a transistor body region. The evaporation deposition of the LaAlO3 film is performed using two electron guns to evaporate dry pellets of Al2O3 and La2O3. The two rates for evaporating the materials are selectively chosen to provide a dielectric film composition having a predetermined dielectric constant ranging from the dielectric constant of an Al2O3 film to the dielectric constant of a La2O3 film.

Abstract: A compensation component and a process for production thereof includes a semiconductor body having first and second electrodes, a drift zone disposed therebetween, and areas of a first conductivity type and a second conductivity type opposite the first conductivity type disposed in the drift zone. Higher doped zones of the first type are inlaid in a weaker doped environment of the second type closer to the first electrode and higher doped zones of the second type are inlaid in a weaker doped environment of the first type closer to the second electrode. The drift zone is complementary so that, in a direction between the electrodes, a more highly doped zone of the first type adjoins a more weakly doped environment of the first type, and a more weakly doped environment of the second type adjoins a more highly doped zone of the second type.

Abstract: A method of fabricating dual gate oxide thicknesses comprising the following steps. A substrate is provided having a first pillar and a second pillar. A gate dielectric layer is formed over the substrate and the first and second pillars. First and second thin spacers are formed over the gate dielectric layer covered side walls of the first and second pillars respectively. The second pillar is masked leaving the first pillar unmasked. The first thin spacers are removed from the unmasked first pillar. The mask is removed from the masked second pillar. The structure is oxidized to convert the second thin spacers to second preliminary gate oxide over the previously masked second pillar and to form first preliminary gate oxide over the unmasked first pillar. The second gate oxide over the second pillar being thicker than the first gate oxide over the first pillar.

Abstract: A process forms a power semiconductor device with reduced input capacitance and improved switching speed. A substrate with an epitaxial has an oxide layer patterned to form a narrow terraced gate. A gate oxide layer is formed on the upper surface of the epitaxial layer. A layer of polysilicon is deposited on the narrow terraced gate oxide region and the gate oxide layer. The polysilicon layer is anisotropically etched to form polysilicon spacers abutting each of the two side surfaces of the narrow terraced gate region. A p-type dopant is implanted through the gate oxide layer and the polysilicon spacers and is driven in to form P-well regions in the epitaxial layer. A source mask is formed and an n-type dopant is implanted through the gate oxide layer and the polysilicon spacers. It is driven in to form N+ source regions in the P-well regions.

Abstract: A method is provided for forming a power semiconductor device. The method begins by providing a substrate of a first conductivity type and then forming a voltage sustaining region on the substrate. The voltage sustaining region is formed by depositing an epitaxial layer of a first conductivity type on the substrate and forming at least one trench in the epitaxial layer. At least one doped column having a dopant of a second conductivity type is located in the epitaxial layer, adjacent a sidewall of the trench. The trench is etched using an etchant gas that also serves as a dopant source for the formation of the doped column. For example, if a p-type dopant such as boron is desired, BCl3 may be used as the etchant gas. Alternatively, if an n-type dopant such as phosphorus is required, PH3 may be used as the etchant gas. The dopant present in the gas is incorporated into the silicon defining the surfaces of the trench. This dopant is subsequently diffused to form the doped column surrounding the trench.

Abstract: The present invention discloses a vertical transistor wherein source/drain regions are formed by using a self-alignment method without using a latest photolithography, channels are formed via a selective epitaxial growth (hereinafter, referred to as ‘SEG’) method and gate oxide films are formed at the both ends of channels to be more efficient than devices having the same channel length, and a method of manufacturing thereof, the vertical transistor comprising: a source region formed on a semiconductor substrate; a drain region formed substantially above the source region; a vertical channel, one end of the channel being contact to the source region and the other end being contact to the drain region; and a gate electrode, formed on the substrate, surrounding the sides of the channel and the drain region, said gate electrode electrically isolated with the source region by a nitride pattern disposed therebetween, isolated with the drain region by a nitride spacer formed on the sidewalls of the drai

Abstract: In a method of fabricating a semiconductor device having a MISFET of trench gate structure, a trench is formed from a major surface of a semiconductor layer of first conductivity type which serves as a drain region, in a depth direction of the semiconductor layer, a gate insulating film including a thermal oxide film and a deposited film is formed over the internal surface of the trench, and after a gate electrode has been formed in the trench, impurities are introduced into the semiconductor substrate of first conductivity type to form a semiconductor region of second conductivity type which serves as a channel forming region, and impurities are introduced into the semiconductor region of second conductivity type to form the semiconductor region of first conductivity type which serves as a source region.

Abstract: A memory cell having a transistor and a capacitor formed in a silicon substrate. The capacitor is formed with a lower electrically conductive plate etched in a projected surface area of the silicon substrate. The lower electrically conductive plate has at least one cross section in the shape of a vee, where the sides of the vee are disposed at an angle of about fifty-five degrees from a top surface of the silicon substrate. The surface area of the lower electrically conductive plate is about seventy-three percent larger than the projected surface area of the silicon substrate in which the lower electrically conductive plate is etched. A capacitor dielectric layer is formed of a first deposited dielectric layer, which is disposed adjacent the lower electrically conductive plate. A top electrically conductive plate is disposed adjacent the capacitor dielectric layer and opposite the lower electrically conductive plate.

Abstract: A method for fabricating a highly integrated transistor comprises the steps of forming a first conductive well region on a silicon substrate, forming an isolation oxide layer on the desired region of the entire surface of the silicon substrate, forming a first pad oxide layer on the entire surface of the silicon substrate, forming a second conductive LDD (low doped drain) region and a second source/drain region on an active region of the silicon substrate, and forming a pad nitride layer on the first oxide layer.

Abstract: A vertically oriented FET having a self-aligned dog-bone structure as well as a method for fabricating the same are provided. Specifically, the vertically oriented FET includes a channel region, a source region and a drain region. The channel region has a first horizontal width and the source and drain regions having a second horizontal width that is greater than the first horizontal width. Each of the source and drain regions have tapered portions abutting the channel region with a horizontal width that varies in a substantially linear manner from the first horizontal width to the second horizontal width.

Abstract: The present invention provides a double gated transistor and a method for forming the same that results in improved device performance and density. The preferred embodiment of the present invention provides a double gated transistor with asymmetric gate doping, where one of the double gates is doped degenerately n-type and the other degenerately p-type. By doping one of the gates n-type, and the other p-type, the threshold voltage of the resulting device is improved. Additionally, the preferred transistor design uses an asymmetric structure that results in reduced gate-to-drain and gate-to-source capacitance. In particular, dimensions of the weak gate, the gate that has a workfunction less attractive to the channel carriers, are reduced such that the weak gate does not overlap the source/drain regions of the transistor. In contrast the strong gate, the gate having a workfunction that causes the inversion layer to form adjacent to it, is formed to slightly overlap the source/drain regions.

Abstract: A semiconductor device, comprising: a semiconductor substrate comprising silicon carbide of a first conductivity type; a silicon carbide epitaxial layer of the first conductivity type; a first semiconductor region formed on the semiconductor substrate and comprising silicon carbide of a second conductivity type; a second semiconductor region formed on the first semiconductor region, comprising silicon carbide of the first conductivity type and separated from the semiconductor substrate of the first conductivity type by the first semiconductor region; a third semiconductor region formed on the semiconductor region, connected to the semiconductor substrate and the second semiconductor region, comprising silicon carbide of the first conductivity type, and of higher resistance than the semiconductor substrate; and a gate electrode formed on the third semiconductor region via an insulating layer; wherein the third semiconductor layer is depleted when no voltage is being applied to the gate electrode so that said s

Abstract: A sidewall spacer is formed in a CMOS device by depositing a layer of silicon nitride on a wafer and anisotropically etching away the silicon nitride layer with a chorine-based plasma etchant.

Abstract: A vertical thin film transistor formed in a single grain of polysilicon having few or no grain boundaries for use in memory, logic and display applications. The transistor is formed from a thin film of polysilicon having large columnar grains, in which source and drain regions have been formed. The large grain size and columnar grain orientation of the thin film are provided by recrystallizing a thin amorphous silicon film, or by specialized deposition of the thin film. Use of a thin film permits the transistor to be formed on an insulating substrate such as glass, quartz, or inexpensive silicon rather than a semiconductor chip, thereby significantly decreasing device cost.

Abstract: A DRAM memory cell includes a MOSFET selection transistor having a drain region and a source region in a semiconductor substrate column. A current channel, which is capable of being actuated by a control gate electrode extends in a vertical direction between the drain and source regions. A capacitor is stacked under the selection transistor and electrically connected to the source region in the semiconductor substrate column. Above the selection transistor is a metal bit line electrically connected to the drain region in the semiconductor substrate column. A metal word line in direct electrical communication with the control gate electrode of the selection transistor extends perpendicularly with respect to the metal bit line.

Abstract: A quick punch-through integrated gate bipolar transistor (IGBT) includes a drift region and a gate. The drift region has a drift region dopant concentration and a drift region thickness. The gate has a gate capacitance. The drift region dopant concentration, drift region thickness and gate capacitance are adjusted dependent at least in part upon the PNP gain of the IGBT to maintain the potential difference between the gate and emitter at a level greater than the IGBT threshold voltage when the collector voltage reaches the bus voltage. This insures that the hole carrier concentration remains approximately equal to or greater than the drift region dopant concentration when the depletion layer punches through to the buffer region during the turn-off delay. Thus, the collector voltage overshoot and the rate of change of voltage and current are controlled, and electromagnetic interference is reduced, during turn off.

Abstract: Methods forming a trench region of a trench capacitor structure having increase surface area are provided. One method includes the steps of forming a discontinuous polysilicon layer on exposed walls of a lower trench region, the discontinuous polysilicon layer having gaps therein which expose portions of said substrate; oxidizing the lower trench region such that the exposed portions of said substrate provided by the gaps in the discontinuous polysilicon layer are oxidized into oxide material which forms a smooth and wavy layer with the discontinuous polysilicon layer; and etching said oxide material so as to form smooth hemispherical grooves on the walls of the trench region.

Abstract: It is proposed when forming field-effect transistor devices in a semiconductor substrate for the overlapping region of a source-drain region that is to be provided to be formed directly as a material region, in particular with outdiffusion processes being avoided to the greatest extent. This takes place in particular by forming the connection region or buried-strap region as selectively epitaxially grown-on single-crystal, possibly doped silicon.

Abstract: A semiconductor device is disclosed. The semiconductor device includes one or more charge control electrodes a plurality of charge control electrodes. The one or more charge control electrodes may control the electric field within the drift region of a semiconductor device.

Abstract: A trench DMOS transistor structure is provided that includes at least three individual trench DMOS transistor cells formed on a substrate of a first conductivity type. The plurality of individual DMOS transistor cells is dividable into peripheral transistor cells and interior transistor cells. Each of the individual transistor cells includes a body region located on the substrate, which has a second conductivity type. At least one trench extends through the body region and the substrate. An insulating layer lines the trench. A conductive electrode is located in the trench, which overlies the insulating layer. Interior transistor cells, but not the peripheral transistor cells, each further include a source region of the first conductivity type in the body region adjacent to the trench.

Abstract: A method is provided for forming a power semiconductor device. The method begins by providing a substrate of a first conductivity type and then forming a voltage sustaining region on the substrate. The voltage sustaining region is formed by depositing an epitaxial layer of a first conductivity type on the substrate and forming at least one terraced trench in the epitaxial layer. The terraced trench has a plurality of portions that differ in width to define at least one annular ledge therebetween. A barrier material is deposited along the walls of the trench. A dopant of a second conductivity type is implanted through the barrier material lining the annular ledge and said trench bottom and into adjacent portions of the epitaxial layer. The dopant is diffused to form at least one annular doped region in the epitaxial layer and at least one other region located below the annular doped region.

Abstract: A method of manufacturing a vertical transistor. A doped region is formed in a substrate. We form sequentially on the substrate: a first spacer dielectric layer, a first gate electrode, a second spacer dielectric layer, a second gate electrode and a third spacer dielectric layer. A trench is formed through the first spacer dielectric layer, the first gate electrode, the second spacer dielectric layer, the second gate electrode and the third spacer dielectric layer. The trench has sidewalls. A gate dielectric layer is formed over the sidewalls of the trench. We form sequentially, in the trench: a first doped layer, a first channel layer, a second doped layer, a third doped layer, a second channel layer, and a fourth doped layer. A cap layer is formed over the structure. Contacts are preferably formed to the doped region, doped layers and gate electrodes.

Abstract: A semiconductor memory device is manufactured by uniformly forming an epitaxial capacitor layer on the whole surface of a single-crystal semiconductor layer, finely dividing the capacitor layer into individual capacitors by etching, using the individual capacitors as a mask to etch the single-crystal semiconductor layer and forming semiconductor columnar portions, and preparing vertical field effect transistors each having a channel portion in the semiconductor columnar portion. Thereby, the vertical field effect transistor can be formed under the epitaxial capacitor in a self aligning manner.

Abstract: A MOS-gated power semiconductor device is described. The MOS-gated power semiconductor device includes a semiconductor substrate that is heavily doped with impurities of a first conductivity type and used as a collector region, a drift region lightly doped with impurities of a second conductivity type on the substrate, a gate insulating layer on the drift region having a center thicker than its edges, a gate electrode on the gate insulating layer, a well region that is lightly doped with impurities of a first conductivity type on the drift region and that has a channel region overlapping a portion of the gate electrode, an emitter region that is heavily doped with impurities of a second conductivity type and that contacts the channel region, an emitter electrode electrically connected to the emitter region and isolated from the gate electrode, and a collector electrode electrically connected to the semiconductor substrate.

Abstract: A process for fabricating a CMOS integrated circuit with vertical MOSFET devices is disclosed. In the process, at least three layers of material are formed sequentially on a semiconductor substrate. The three layers are arranged such that the second layer is interposed between the first and third layers. The second layer is sacrificial, that is, the layer is completely removed during subsequent processing. The thickness of the second layer defines the physical gate length of the vertical MOSFET devices.

Abstract: Compact trench-gate semiconductor devices, for example a cellular power MOSFET with sub-micron pitch (Yc), are manufactured with self-aligned techniques that use sidewall spacers (52) in different ways. The trench-gate (11) is accommodated in a narrow trench (20) that is etched via a narrow window (52b) defined by the spacers (52) at sidewalls of a wider window (51a) of a mask (51) at the body surface (10a). The spacers (52) permit a source region (13) adjacent to the trench-gate (11) and an insulating overlayer (18) over the trench-gate (11) to be self-aligned to this narrow trench (20). The overlayer (18), which defines a contact window (18a) for a source electrode (33), is provided in a simple but reproducible manner by deposition and etch-back, after removing the spacers (52). Its overlap (y4, y4′) with the body surface (10a) is well-defined, so reducing a short-circuit risk between the source electrode (33) and the trench-gate (11).

Abstract: A vertical Field Effect Transistor (FET) that may be an N-type FET (NFET) or a P-type FET (PFET); a multi-device vertical structure that may be two or more NFETs or two or more PFETs; logic gates including at least one vertical FET or at least one multi-device vertical; a Static Random Access Memory (SRAM) cell and array including at least one vertical FET; a memory array including at least one such SRAM cell; and the process of forming the vertical FET structure, the vertical multi-device (multi-FET) structure, the logic gates and the SRAM cell. The vertical FETs are epitaxially grown layered stacks of NPN or PNP with the side of a polysilicon gate layer adjacent the device's channel layer. The multi-FET structure may be formed by forming sides of two or more gates adjacent to the same channel layer or, by forming multiple channel layers in the same stack, e.g., PNPNP or NPNPN, each with its own gate, i.e., the side of a polysilicon gate layer.

Abstract: A semiconductor component includes a first connection zone of a first conductivity type for providing a contact at a first side of a semiconductor body and a second connection zone of the first conductivity type for providing a contact at the second side of the semiconductor body. A drift zone adjoins the first connection zone and extends in a vertical direction of the semiconductor body as far as the second side of the semiconductor body. A body zone of a second conductivity type is disposed between the second connection zone and the first connection zone or the drift zone. A control electrode is insulated from the semiconductor body and disposed above the body zone such that the control electrode substantially does not overlap with the drift zone and the second connection zone in a lateral direction. A method for manufacturing a semiconductor component is also provided.

Abstract: A method of fabricating an isolated vertical transistor comprising the following steps. A wafer having a first implanted region selected from the group comprising a source region and a drain region is provided. The wafer further includes STI areas on either side of a center transistor area. The wafer is patterned down to the first implanted region to form a vertical pillar within the center transistor area using a patterned hardmask. The vertical pillar having side walls. A pad dielectric layer is formed over the wafer, lining the vertical pillar. A nitride layer is formed over the pad dielectric layer. The structure is patterned and etched through the nitride layer and the pad dielectric layer; and into the wafer within the STI areas to form STI trenches within the wafer. The STI trenches are filled with insulative material to form STIs within STI trenches. The patterned nitride and pad dielectric layers are removed. The patterned hardmask is removed.

Abstract: In a method of fabricating a semiconductor device having a MISFET of trench gate structure, a trench is formed from a major surface of a semiconductor layer of first conductivity type which serves as a drain region, in a depth direction of the semiconductor layer, a gate insulating film including a thermal oxide film and a deposited film is formed over the internal surface of the trench, and after a gate electrode has been formed in the trench, impurities are introduced into the semiconductor substrate of first conductivity type to form a semiconductor region of second conductivity type which serves as a channel forming region, and impurities are introduced into the semiconductor region of second conductivity type to form the semiconductor region of first conductivity type which serves as a source region.

Abstract: A method of manufacturing a vertical transistor. The vertical transistor utilizes a deposited amorphous silicon layer to form a source region. The vertical gate transistor includes a double gate structure for providing increased drive current. A wafer bonding technique can be utilized to form the substrate.

Abstract: A power MOSFET type device, which can include an IGBT or other VDMOS device having similar forward transfer characteristics, is formed with an asymmetrical channel, to produce different gate threshold voltage characteristics in different parts of the device. The different gate threshold voltage characteristics can be achieved either by different source region doping concentrations or different body region doping concentrations subjacent the gate oxide, or by asymmetrical gate oxide thicknesses. The portion of overall channel affected can be 50% or such other proportion as the designer chooses, to reduce the zero temperature coefficient point of the device and improve its Safe Operating Area in linear operation, while retaining low conduction loss. Multiple power MOSFET devices with asymmetrical channels can easily be used safely in parallel linear power amplifier circuits.

Abstract: A power MOSFET comprising a drain layer of a first conductivity type, a drift layer of the first conductivity type provided on the drain layer, a base layer of a first or a second conductivity type provided on the drift layer, a source region of the first conductivity type provided on the base layer, a gate insulating film formed on an inner wall surface of a trench penetrating the base layer and reaching at the drift layer, and a gate electrode provided on the gate insulating film inside the trench, wherein the gate insulating film is formed such that a portion thereof adjacent to the drift layer is thicker than a portion thereof adjacent to the base layer, and the drift layer has an impurity concentration gradient higher in the vicinity of the drain layer and lower in the vicinity of the source region along a depth direction of trench.

Abstract: A memory cell comprises a region containing one or more vertical pass transistor, and a support region containing, e.g. one or more planar transistors. During processing, a polysilicon layer is formed for the planar devices gate. The polysilicon layer is removed from the array region by etching with a first etch mask. A subsequently formed insulating oxide layer is formed and removed from over the polysilicon (i.e. the support region) by etching with a second etch mask. Because the polysilicon layer is left intact only where it is needed, above the region with the planar devices, and the oxide layer is left intact only where it is needed, above the region with the vertical devices, the resulting structure has a substantially planar top surface, allowing for optional subsequent metal depositions and structuring as a wiring level.

Abstract: A trench MOSFET transistor device and method of making the same are provided. The trench MOSFET transistor device comprises: (a) a drain region of first conductivity type; (b) a body region of a second conductivity type provided over the drain region, such that the drain region and the body region form a first junction; (c) a source region of the first conductivity type provided over the body region, such that the source region and the body region form a second junction; (d) source metal disposed on an upper surface of the source region; (e) a trench extending through the source region, through the body region and into the drain region; and (f) a gate region comprising (i) an insulating layer, which lines at least a portion of the trench and (ii) a conductive region, which is disposed within the trench adjacent the insulating layer. The body region in this device is separated from the source metal.

Abstract: A drift layer is formed on a substrate. A base region is formed on the drift layer. A plurality of source regions are formed in a surficial layer of the base region. A plurality of gate electrodes face to the base region and the source region via a gate insulating film. A source electrode is brought into contact with the base region and the source region. A nitrogen cluster containing layer is embedded in the drift layer so as to extend laterally under the base region so that at least part of the drift region is left under the nitrogen cluster containing layer.

Abstract: This invention relates to a method for forming a metal oxide semiconductor type field effect transistor (MOSFET), more particularly, to the method for forming the MOSFET by forming a gate and a spacer in a trench. The present invention is used to form the gate and the spacer of the MOSFET in the trench which is preformed in the substrate to reduce the junction depth of the source/drain region. The present invention also can reduce the defects in the drain induced barrier lowering and the punch-through leakage to avoid the spiking leakage defects in the back-end process.

Abstract: A semiconductor device includes a semiconductor substrate; a gate oxide film made on the semiconductor substrate; and first transistors each having a first gate formed on the gate oxide film and a pair of source/drain formed in confrontation in the semiconductor substrate. The gate oxide film has a higher nitrogen concentration in its portion nearer to the first gates than that of its portion nearer to the semiconductor substrate.

Abstract: Power MOSFET devices provide highly linear transfer characteristics (e.g., Id v. Vg) and can be used effectively in linear power amplifiers. These linear transfer characteristics are provided by a device having a channel that operates in a linear mode and a drift region that simultaneously supports large voltages and operates in a current saturation mode. A relatively highly doped transition region is provided between the channel region and the drift region. Upon depletion, this transition region provides a potential barrier that supports simultaneous linear and current saturation modes of operation. Highly doped shielding regions may also be provided that contribute to depletion of the transition region.

Abstract: The present invention provides a method for fabricating a recessed field-effect transistor, comprising steps of: providing a silicon substrate; forming a first dielectric layer on said substrate; patterning said first dielectric layer so as to form a window; forming a gate dielectric layer on said substrate inside said window; forming a poly-silicon layer covering said gate dielectric layer and said first dielectric layer; etching back said poly-silicon layer after said first dielectric layer is exposed, leaving poly-silicon in said window; forming a metal layer covering said poly-silicon layer and said first dielectric layer; removing said metal layer outside said window; removing said first dielectric layer on said substrate; and heavily doping ions so as to form heavily doped regions.

Abstract: Using current technology, the only way to further increase device density is to decrease device pitch. The present invention achieves this by introducing a sidewall doping process that effectively reduces the source width, and hence the pitch. This sidewall doping process also eliminates the need for a source implantation mask while the sidewall spacer facilitates silicide formation at the source, the P body contact, and the polysilicon gate simultaneously. Since the source and P body are fully covered by silicide, the contact number and contact resistance can be minimized. The silicided polysilicon gate has a low sheet resistance of about 4-6 ohm/square, resulting in a higher operating frequency.

Abstract: A super-self-aligned (SSA) structure and manufacturing process uses a single photomasking layer to define critical features and dimensions of a trench-gated vertical power DMOSFET. The single critical mask determines the trench surface dimension, the silicon source-body mesa width between trenches, and the dimensions and location of the silicon mesa contact. The contact is self-aligned to the trench, eliminating the limitation imposed by contact-to-trench mask alignment in conventional trench DMOS devices needed to avoid process-induced gate-to-source shorts. Oxide step height above the silicon surface is also reduced avoiding metal step coverage problems. Poly gate bus step height is also reduced. Other features described include polysilicon diode formation, controlling the location of drain-body diode breakdown, reducing gate-to-drain overlap capacitance, and utilizing low-thermal budget processing techniques.

Abstract: A power MOSFET has a plurality of spaced rows of parallel coextensive trenches. The trenches are lined with a gate oxide and are filled with a single common layer of conductive polysilicon which extends into each trench and overlies the silicon surface which connects adjacent trenches. The source contact is made at a location remote from the trenches and between the rows of trenches. The trenches are 1.8 microns deep, are 0.6 microns wide and are spaced by about 0.6 microns or greater. The trench is from 0.2 to 0.25 microns deeper than the channel region. The device has a very low figure of merit and is useful especially in low voltage circuits.

Abstract: A gate isolation structure of a semiconductor device and method of making the same provides a trench in a silicon substrate, wherein a dielectric layer is formed on sidewalls and bottom of the trench, the dielectric layer having a first thickness on the sidewalls and a second thickness at the bottom that is greater than the first thickness. The thicker dielectric layer at the bottom substantially reduces gate charge to reduce the Miller Capacitance effect, thereby increasing the efficiency of the semiconductor device and prolonging its life.