Abstract: A power cell designed for an RF power amplifier comprises an enhancement MOSFET formed in an P-Well in an P-Substrate and a depletion or Schottky MOSFET formed in an N-Well in the same P-Substrate with a horizontal or a vertical channel between the source, drain, and gate electrodes of the depletion or Schottky MOSFET. The source node of the enhancement MOSFET and source node of the depletion or Schottky MOSFET are connected together to form the power cell.

Abstract: A semiconductor device includes a first compound semiconductor layer on a substrate, first through third electrodes spaced apart from each other on the first compound semiconductor layer, a second compound semiconductor layer on the first compound semiconductor layer between the first through third electrodes, a third compound semiconductor layer on the second compound semiconductor layer between the first and second electrodes, a first gate electrode on the third compound semiconductor layer, a fourth compound semiconductor layer having a smaller thickness than the third compound semiconductor layer on a portion of the second compound semiconductor layer between the second and third electrodes, and a second gate electrode on the fourth compound semiconductor layer. The first compound semiconductor layer between the second and third electrodes includes a 2-dimensional electron gas (2DEG) and the third compound semiconductor layer includes a 2-dimensional hole gas (2DHG).

Abstract: A device with N-Channel and P-Channel III-Nitride field effect transistors comprising a non-inverted P-channel III-Nitride field effect transistor on a first nitrogen-polar nitrogen face III-Nitride material, a non-inverted N-channel III-Nitride field effect transistor, epitaxially grown, a first III-Nitride barrier layer, two-dimensional hole gas, second III-Nitride barrier layer, and a two-dimensional hole gas. A method of making complementary non-inverted P-channel and non-inverted N-channel III-Nitride FET comprising growing epitaxial layers, depositing oxide, defining opening, growing epitaxially a first nitrogen-polar III-Nitride material, buffer, back barrier, channel, spacer, barrier, and cap layer, and carrier enhancement layer, depositing oxide, growing AlN nucleation layer/polarity inversion layer, growing gallium-polar III-Nitride, including epitaxial layers, depositing dielectric, fabricating P-channel III-Nitride FET, and fabricating N-channel III-Nitride FET.

Abstract: A device with complementary non-inverted N-channel and inverted P-channel field effect transistors comprising a layer grown epitaxially on a substrate, a barrier layer, a two-dimensional electron gas in the first III-Nitride epitaxial layer, a second III-Nitride material layer, and a two-dimensional hole gas in the second III-Nitride epitaxial layer. A device with complementary inverted N-channel and non-inverted P-channel field effect transistors comprising a nitrogen-polar III-Nitride layer grown epitaxially, a barrier material layer, a two-dimensional hole gas, and a two-dimensional electron gas in the second III-Nitride epitaxial layer. A method of making complementary inverted P-channel and non-inverted N-channel III-Nitride field effect transistors. A method of making a complementary non-inverted P-channel field effect transistor and inverted N-channel III-Nitride field effect transistor on a substrate.

Abstract: The embodiments of the present invention provide a Ge-based NMOS device structure and a method for fabricating the same. By using the method, double dielectric layers of germanium oxide (GeO2) and metal oxide are deposited between the source/drain region and the substrate. The present invention not only reduces the electron Schottky barrier height of metal/Ge contact, but also improves the current switching ratio of the Ge-based Schottky and therefore, it will improve the performance of the Ge-based Schottky NMOS transistor. In addition, the fabrication process is very easy and completely compatible with the silicon CMOS process. As compared with conventional fabrication method, the Ge-based NMOS device structure and the fabrication method in the present invention can easily and effectively improve the performance of the Ge-based Schottky NMOS transistor.

Abstract: A disclosed semiconductor device includes a semiconductor deposition layer formed over an insulation structure and above a substrate. The device includes a gate formed over a contact region between first and second implant regions in the semiconductor deposition layer. The first and second implant regions both have a first conductivity type, and the gate has a second conductivity type. The device may further include a second gate formed beneath the semiconductor deposition layer.

Abstract: The present invention relates to fabrication of enhancement mode and depletion mode High Electron Mobility Field Effect Transistors on the same die separated by as little as 10 nm. The fabrication method uses selective decomposition and selective regrowth of the Barrier layer and the Cap layer to engineer the bandgap of a region on a die to form an enhancement mode region. In these regions zero or more devices may be fabricated.

Abstract: A method of manufacturing Schottky diodes in a CMOS process includes forming wells, including first wells (16) for forming CMOS devices and second wells (18) for forming Schottky devices. Then, transistors are formed in the first wells, the second wells protected with a protection layer (20) and suicide contacts (40) formed to source and drain regions in the first wells. The protection layer is then removed, a Schottky material deposited and etched away except in a contact region in each second well to form a Schottky contact between the Schottky material (74) and each second well (18).

Abstract: An Enhancement-mode (E-mode) high electron mobility transistor (HEMT) includes a channel layer with a 2-Dimensional Electron Gas (2DEG), a barrier layer inducing the 2DEG in the channel layer, source and drain electrodes on the barrier layer, a depletion layer on the barrier layer between the source and drain electrodes, and a gate electrode on the depletion layer. The barrier layer is recessed below the gate electrode and the depletion layer covers a surface of the recess and extends onto the barrier layer around the recess.

Abstract: A method of manufacturing a semiconductor device is disclosed. The method includes forming a first trench and a second trench in an n-type substrate surface, the first trenches being spaced apart from each other, the second trench surrounding the first trenches, the second trench being wider than the first trench. The method also includes forming a gate oxide film on the inner surfaces of the first and second trenches, and depositing an electrically conductive material to the thickness a half or more as large as the first trench width. The method further includes removing the electrically conductive material using the gate oxide film as a stopper layer, forming an insulator film thicker than the gate oxide film, and polishing the insulator film by CMP for exposing the n-type substrate and the electrically conductive material in the first trench.

Abstract: An emissive device includes a substrate; a switching element disposed on a surface of the substrate; an insulating layer covering the switching element; a contact hole disposed in the insulating layer; a first electrode disposed on a surface of the insulating layer and electrically connected to the switching element via the contact hole in the insulating layer; a second electrode disposed at a side opposite the substrate with respect to the first electrode; a luminescent layer disposed between the first electrode and the second electrode; and a light shield disposed at a side from which light from the luminescent layer emerges and having a portion covering the contact hole when viewed in a direction perpendicular to the substrate.

Abstract: Disclosed are embodiments of a field effect transistor (FET) having decreased drive current temperature sensitivity. Specifically, any temperature-dependent carrier mobility change in the FET channel region is simultaneously counteracted by an opposite strain-dependent carrier mobility change to ensure that drive current remains approximately constant or at least within a predetermined range in response to temperature variations. This opposite strain-dependent carrier mobility change is provided by a straining structure that is configured to impart a temperature-dependent amount of a pre-selected strain type on the channel region. Also disclosed are embodiments of an associated method of forming the field effect transistor.

Abstract: A process for fabricating a semiconductor device. The process including (a) growing a channel layer on a buffer layer, (b) growing a barrier layer on the channel layer, (c) epitaxially growing a quaternary etch-stop layer on the barrier layer, (d) growing a first contact layer on the quaternary etch-stop layer, (e) growing a second contact layer on the first contact layer, (f) etching portions of the second contact layer to reveal a first recess surface, and (g) etching portions of the first contact layer to reveal a second recess surface. The second contact layer may be a highly doped contact layer. The second recess surface generally forms a gate region. The first and the second contact layers have a first etch rate and the quaternary etch-stop layer has a second etch rate in a chosen first etch chemistry.

Abstract: A method for forming a semiconductor device and a corresponding device are provided. The method includes forming a floating gate device in a process with dual strain layers, and an etch stop layer. An oxide is formed between the floating gate device and a nitride layer above the floating gate.

Abstract: A semiconductor device 1 includes a substrate 2 having on a main surface thereof a central area and a peripheral area which surrounds the central area and is exposed, a semiconductor layer 4 which is formed on the main surface of the substrate 2, is made of a material harder than the substrate 2, is in the shape of a mesa, and has a steep side over the exposed peripheral area, and an insulating film 12S provided on a side surface of the semiconductor layer 4.

Abstract: A CMOS device and method of manufacture is provided for producing an integrated circuit that is not susceptible to various soft errors such as single-event upsets, multi-bit upsets or single-event latchup. The CMOS device and method utilizes a new and novel well architecture in conjunction with metal source/drain electrodes to eliminate soft errors. In one embodiment, the CMOS device uses a first metal source/drain material for the NMOS device and a second metal source/drain material for the PMOS device. The CMOS device further uses a multi-layered well-structure with a shallow N-well and a buried P-well for the PMOS device and a shallow P-well and a buried N-well for the NMOS device.

Abstract: An embedded memory required for a high performance, multifunction SOC, and a method of fabricating the same are provided. The memory includes a bipolar transistor, a phase-change memory device and a MOS transistor, adjacent and electrically connected, on a substrate. The bipolar transistor includes a base composed of SiGe disposed on a collector. The phase-change memory device has a phase-change material layer which is changed from an amorphous state to a crystalline state by a current, and a heating layer composed of SiGe that contacts the lower surface of the phase-change material layer.

Abstract: Monolithic electronic devices are providing including a high bandgap layer. A first type of nitride device is provided on a first portion of the high bandgap layer, the first nitride device including first and second implanted regions respectively defining source and drain regions of the first type of nitride device. A second type of nitride device, different from the first type of nitride device, is provided on a second portion of the high bandgap layer, the second type of nitride device including an implanted highly conductive region. At least a portion of the implanted highly conductive region of the second type of nitride device is coplanar with at least a portion of both the first and second implanted regions of the first type of nitride device.

Abstract: A semiconductor gate stack comprising a silicon oxide based gate dielectric and a doped semiconductor material is formed on a semiconductor substrate. A high-k material metal gate electrode comprising a high-k gate dielectric and a metal gate portion is also formed on the semiconductor substrate. Oxygen-impermeable dielectric spacers are formed on the sidewalls of the semiconductor gate stack and the high-k material metal gate stack. The oxygen-impermeable dielectric spacer on the semiconductor gate stack is removed, while the oxygen impermeable dielectric spacer on the high-k material metal gate electrode is preserved. A low-k dielectric spacer is formed on the semiconductor gate stack, which provides a low parasitic capacitance for the device employing the semiconductor gate stack.

Abstract: Improved Schottky diodes with reduced leakage current and improved breakdown voltage are provided by building a JFET with its current path of a first conductivity type serially located between a first terminal comprising a Schottky contact and a second terminal. The current path lies (i) between multiple substantially parallel finger regions of a second, opposite, conductivity type substantially laterally outboard of the Schottky contact, and (ii) partly above a buried region of the second conductivity type that underlies a portion of the current path, which regions are electrically coupled to the first terminal and the Schottky contact and which portion is electrically coupled to the second terminal. When reverse bias is applied to the first terminal and Schottky contact the current path is substantially pinched off in vertical or horizontal directions or both, thereby reducing the leakage current and improving the breakdown voltage of the device.

Abstract: Monolithic electronic device including a common nitride epitaxial layer are provided. A first type of nitride device is provided on the common nitride epitaxial layer including a first at least one implanted n-type region on the common nitride epitaxial layer. The first at least one implanted n-type region has a first doping concentration greater than a doping concentration of the common nitride epitaxial layer. A second type of nitride device, different from the first, including a second at least one implanted n-type region is provided on the common nitride epitaxial layer. The second at least one implanted n-type region is different from the first at least one implanted n-type region and has a second doping concentration that is greater than the doping concentration of the common nitride epitaxial layer. First and second pluralities of contacts respectively define first and second electronic devices on the common nitride epitaxial layer.

Abstract: Merged P-i-N Schottky device in which the oppositely doped diffusions extend to a depth and have been spaced apart such that the device is capable of absorbing a reverse avalanche energy comparable to a Fast Recovery Epitaxial Diode having a comparatively deeper oppositely doped diffusion region.

Abstract: A Schottky diode capable of sustaining a voltage of greater than about 250 volts and a method for its manufacture. An epitaxial layer of N-type conductivity is disposed on a semiconductor substrate of N-type conductivity. A guard ring of P-type conductivity extends into the epitaxial layer from its surface. A stacked structure is formed on a portion of the guard ring and a portion of the epitaxial layer. The stacked structure includes a layer of semi-insulating semiconductor material disposed on a layer of dielectric material. A first metal layer is formed on the portion of the epitaxial layer adjacent a first side of the stacked structure and on a first portion of the stacked structure. A second metal layer is formed on the portion of the epitaxial layer adjacent a second side of the stacked structure and on a second portion of the stacked structure.

Abstract: A semiconductor device includes: a first group-III nitride semiconductor layer formed on a substrate; a second group-III nitride semiconductor layer made of a single layer or two or more layers, formed on the first group-III nitride semiconductor layer, and acting as a barrier layer; a source electrode, a drain electrode, and a gate electrode formed on the second group-III nitride semiconductor layer, the gate electrode controlling a current flowing between the source and drain electrodes; and a heat radiation film with high thermal conductivity which covers, as a surface passivation film, the entire surface other than a bonding pad.

Abstract: An anneal of a gate recess prior to formation of a gate contact, such as a Schottky contact, may reduce gate leakage and/or provide a high quality gate contact in a semiconductor device, such as a transistor. The use of an encapsulation layer during the anneal may further reduce damage to the semiconductor in the gate recess of the transistor. The anneal may be provided, for example, by an anneal of ohmic contacts of the device. Thus, high quality gate and ohmic contacts may be provided with reduced degradation of the gate region that may result from providing a recessed gate structure as a result of etch damage in forming the recess.

Abstract: A method for fabricating devices in a multi-layer structure adapted for the formation of enhancement mode high electron mobility transistors, depletion mode high electron mobility transistors, and power high electron mobility transistors includes defining gate recesses in the structure. The structure has, on a substrate, a channel layer, spacer layer on the channel layer, a first Schottky layer, a second Schottky layer on the first Schottky layer, and a third Schottky layer on the second Schottky layer, and a contact layer on the third Schottky layer. Etch stops are defined intermediate the first and second Schottky layers, intermediate the second and third Schottky layers, and intermediate the third Schottky layer and the contact layer.

Abstract: A technique capable of reducing threshold voltage and reducing high-temperature heat treatment after forming a gate electrode is provided. An n-type MIS transistor or a p-type MIS transistor is formed on an active region isolated by an element isolation region of a semiconductor substrate. In the n-type MIS transistor, a gate electrode is formed through a gate insulating film, and the gate electrode is composed of a hafnium silicide film. On the other hand, in the p-type MIS transistor, a gate electrode is formed through a gate insulating film, and the gate electrode is composed of a platinum silicide film. Also, the gate electrodes are formed after the activation annealing (heat treatment) for activating impurities implanted into a source region and a drain region.

Abstract: A planar combined structure of a bipolar junction transistor (BJT) and n-type/p-type metal semiconductor field-effect transistors (MESFETs) and a method for forming the structure. The n-type GaN MESFET is formed at the same time when an inversion region (an emitter region) of the GaN BJT is formed by an ion implantation or impurity diffusion method by using a particular mask design, while a p-type GaN region is at the same time is formed as the p-type GaN MESFET. Namely, the n-type channel of the n-type MESFET is formed by the ion implantation or impurity diffusion method when the BJT is formed with the same ion implantation or impurity diffusion method performed, while a region of the p-type GaN without being subject to the ion implantation or impurity diffusion method is formed as the p-type MESFET. As such, the BJT is formed currently with the n-type/p-type MESFETs on the same GaN crystal growth layer as a planar structure.

Abstract: The present invention provides a unit cell of a metal-semiconductor field-effect transistor (MESFET). The unit cell of the MESFET includes a source, a drain and a gate. The gate is disposed between the source and the drain and on an n-type conductivity channel layer. A p-type conductivity region is provided beneath the source and has an end that extends towards the drain. The p-type conductivity region is spaced apart from the n-type conductivity channel region and is electrically coupled to the source.

Abstract: An anneal of a gate recess prior to formation of a gate contact, such as a Schottky contact, may reduce gate leakage and/or provide a high quality gate contact in a semiconductor device, such as a transistor. The use of an encapsulation layer during the anneal may further reduce damage to the semiconductor in the gate recess of the transistor. The anneal may be provided, for example, by an anneal of ohmic contacts of the device. Thus, high quality gate and ohmic contacts may be provided with reduced degradation of the gate region that may result from providing a recessed gate structure as a result of etch damage in forming the recess.

Abstract: In a method of forming a semiconductor device with a first channel layer formed over a portion of a second channel layer, a portion of the second channel underlying the first channel is etched so as to form an overhanging ledge in the first channel, and then a metallic contact disposed on top of the ledge portion is diffused into the first channel by ohmic alloying to form an electrode in the first channel.

Abstract: A Schottky diode includes a semiconductor substrate made of 4H—SiC, an epitaxially grown 4H—SiC layer, an ion implantation layer, a Schottky electrode, an ohmic electrode, and an insulative layer made of a thermal oxide film. The Schottky electrode and the insulative layer are not in contact with each other, with a gap being provided therebetween, whereby an altered layer does not occur. Therefore, it is possible to suppress the occurrence of a leak current.

Abstract: The invention concerns a method for making a vertical Schottky diode on a highly doped N-type silicon carbide substrate (1), comprising steps which consist in forming an N-type lightly doped epitaxial layer (2); etching out a peripheral trench at the active zone of the diode; forming a type P doped epitaxial layer; carrying out a planarization process so that a ring (6) of the P type epitaxial layer remains in the trench; forming an insulating layer (3) on the outer periphery of the component, said insulating layer partly covering said ring; and depositing a metal (4) capable of forming a Schottky barrier with the N type epitaxial layer.

Abstract: Various methods for forming semiconductor devices are provided that include the step of implanting dopants into the devices to achieve doping concentrations that allow complementary n- and p-channel SJT behavior with devices of substantially equal gate length and gate width. Moreover, complementary SJT devices are provided that include n- and p-channel devices that have approximately equal gate lengths and widths. SJT devices may be appropriately doped and configured such that input current and the output current both vary substantially exponentially with a gate-source voltage in the sub-threshold mode, and such that the drain current varies substantially linearly with the gate current through a substantially constant current gain that is given by a ratio of the drain current to the gate current.

Abstract: A semiconductor device includes: a silicon substrate; a source/drain region formed in the substrate including a lightly doped region and an adjacent heavily doped region, the depth of the heavily doped region being greater than the depth of the lightly doped region; a gate oxide layer on the silicon substrate; and a notched gate electrode on the substrate, the notched gate electrode including a notch along an outer side surface of a lower portion such that a top portion of the notched gate electrode is wider than the lower portion, the gate oxide layer extending between the interface of the notched gate electrode and the substrate, and a gate poly oxide layer provided along an outer side surface of the notched gate electrode and along an inner wall of the notch, a portion of the lightly doped region being under the notch.

Abstract: Oxidation on the surface of a film of refractory metal constituting a gate electrode (word line WL) is suppressed by forming an insulation film constituting a cap insulation film of the gate electrode (word line WL) at a temperature of 500° C. or lower. Further, oxidation on the surface of the refractory metal film exposed to the side wall of the gate electrode (word line WL) is suppressed by forming an insulation film constituting the side wall spacer of the gate electrode (word line WL) at a temperature of 500° C. or lower.

Abstract: A GaInP epitaxial stacking structure and fabrication method thereof, and a FET transistor using this structure are provided wherein, stacked upon a GaAs single-crystal substrate are at least a buffer layer, a GaZIn1-ZAs (0<Z?1) channel layer, and a GaYIn1?YP (0<Y?1) electron-supply layer joined to the channel layer, wherein the GaInP epitaxial stacking structure includes a region within the electron-supply layer wherein the gallium composition ratio (Y) decreases from the side of the junction interface with the channel layer toward the opposite side.

Abstract: A high temperature thermal annealing process creates a low resistance contact between a metal material and an organic material of an organic semiconductor device, which improves the efficiency of carrier injection. The process forms ohmic contacts and Schottky contacts. Additionally, the process may cause metal ions or atoms to migrate or diffuse into the organic material, cause the organic material to crystallize, or both. The resulting organic semiconductor device has enhanced operating characteristics such as faster speeds of operation. Instead of using heat, the process may use other forms of energy, such as voltage, current, electromagnetic radiation energy for localized heating, infrared energy and ultraviolet energy. An example enhanced organic diode comprising aluminum, carbon C60, and copper is described, as well as example insulated gate field effect transistors.

Abstract: A method for manufacturing a hetero-junction field effect transistor (HFET) device, which includes sequentially forming a non-doped GaN semiconductor layer and an AlGaN semiconductor layer on a substrate, separating devices from each other by etching the substrate, forming a photoresist layer pattern on the AlGaN semiconductor layer and forming gate electrodes by depositing a material on the substrate using the photoresist layer pattern, treating the surface of the AlGaN semiconductor layer, and forming a photoresist layer pattern on the substrate and forming ohmic electrodes by depositing a metal on the substrate using the photoresist layer pattern, is provided. Accordingly, it is possible to overcome a difficulty in aligning the gate electrode with the ohmic electrodes and prevent a substrate from having a step difference introduced by the ohmic electrodes because the gate electrode is formed before the ohmic electrodes are formed.

Abstract: A method of fabricating silicon TFTs (thin-film transistors) is disclosed. The method comprises a crystallization step by laser irradiation effected after the completion of the device structure. First, amorphous silicon TFTs are fabricated. In each of the TFTs, the channel formation region, the source and drain regions are exposed to laser radiation illuminated from above or below the substrate. Then, the laser radiation is illuminated to crystallize and activate the channel formation region, and source and drain regions. After the completion of the device structure, various electrical characteristics of the TFTs are controlled. Also, the amorphous TFTs can be changed into polysilicon TFTs.

Abstract: The illumination energy of an excimer laser is measured and adjusted to always effect illumination at constant energy. A laser beam output from an optics is reflected by a mirror, and applied to a sample. A beam profiler is disposed behind the mirror to measure the energy of an illumination laser beam. An energy attenuating device disposed between another mirror and the optics is operated based on the measurement value so that the energy of the laser beam applied to the sample is kept constant.

Abstract: An emitter includes an electron supply and a tunneling layer disposed on the electron supply. A cathode layer is disposed on the tunneling layer. A conductive electrode has multiple layers of conductive material. The multiple layers include a protective layer disposed on the cathode layer. The conductive electrode has been etched to define an opening thereby exposing a portion of the cathode layer.

Abstract: A semiconductor device having at least one layer of a group III-V semiconductor material epitaxially deposited on a group III-V nucleation layer adjacent to a germanium substrate. By introducing electrical contacts on one or more layers of the semiconductor device, various optoelectronic and microelectronic circuits may be formed on the semiconductor device having similar quality to conventional group III-V substrates at a substantial cost savings. Alternatively, an active germanium device layer having electrical contacts may be introduced to a portion of the germanium substrate to form an optoelectronic integrated circuit or a dual optoelectronic and microelectronic device on a germanium substrate depending on whether the electrical contacts are coupled with electrical contacts on the germanium substrate and epitaxial layers, thereby increase the functionality of the semiconductor devices.

Abstract: A lateral, high-voltage, FET having a low on-resistance and a buried conduction layer comprises a P-type buried layer region within an N-well formed in a P-type substrate. The P-type buried layer region is connected to a drain electrode by a first P-type drain diffusion region that is disposed in the N-well region. The P-type buried layer region is also connected to a second P-type drain diffusion region that extends down from the surface at one end of the PMOS gate region. A P-type source diffusion region, which connects to the source electrode, defines the other end of the gate region.

Abstract: The present invention discloses a method of manufacturing a polycrysalline silicon layer, comprising: depositing an amorphous silicon layer on a substrate; patterning the amorphous silicon layer to form a semiconductor layer having saw-toothed portions at both sides; and scanning the semiconductor layer from the saw-toothed side portion using a laser beam to form a polycyrstalline silicon layer. The laser beam has a line shape elongated in a perpendicular direction to a scanning direction. The grain size can be larger and the number of grain boundaries is reduced.

Abstract: A method of fabricating silicon TFTs (thin-film transistors) is disclosed. The method comprises a crystallization step by laser irradiation effected after the completion of the device structure. First, amorphous silicon TFTs are fabricated. In each of the TFTs, the channel formation region, the source and drain regions are exposed to laser radiation illuminated from above or below the substrate. Then, the laser radiation is illuminated to crystallize and activate the channel formation region, and source and drain regions. After the completion of the device structure, various electrical characteristics of the TFTs are controlled. Also, the amorphous TFTs can be changed into polysilicon TFTs.

Abstract: The invention is a Pseudomorphic transistor structure having a semiconductor layer having a 2DEG layer therein, a Schottky layer, a transition layer and an ohmic contact layer on the transition layer, wherein a double recess structure is disposed through the ohmic layer onto the transition layer in which one or two layers of InyGa1−yP are used as etch-stop layers to define the depth of the recess.

Abstract: In the formation and structure of a thin film transistor (TFT), an insulator is formed to cover the surface of the transistor gate electrode, which electrode is separated from an underlying semiconductor layer, having defined source, drain and channel regions, by a gate insulating layer. The overlying gate insulator is formed by anodic oxidation of the gate electrode metal. The formation of the gate insulator thickness and its lateral offset, .DELTA.L, which is defined as the lateral spatial separation between the gate electrode and the source or drain region, can be accurately controlled by the gate electrode anodic oxidation process to provide a reliably and reproducible low OFF current, I.sub.OFF, resulting in a TFT that provides for a large I.sub.ON /I.sub.OFF ratio useful in large area applications wherein electrical charge is required, such as, liquid crystal displays and memory integrated circuits.

Abstract: A method of fabricating a UMOS semiconductor device includes a blanket implant of an N type dopant into a surface of a substrate (for forming source regions), a high energy implant of a P type dopant into the substrate (for forming body regions), an etch through a hard mask to form trenches and mesas (each of the mesas having a source region at its top and a body region below), and concurrently (i) providing a gate dielectric on the sidewalls of the trenches and (ii) redistributing the dopants so that the body regions extend deeper into the substrate beneath the centers of the mesas than adjacent the walls of the trenches. Contact windows are etched in the mesas to allow electrical contact with the source regions and the body regions. The initial implant of P type dopant may be a blanket implant or an implant through a mask which concentrates the P type dopant in the centers of the mesas.

Abstract: A process is provided for fabricating MODFET's in group III nitride compound semiconductors. The process precedes isolation of the MODFET structure with the use of e-beam lithography to define very narrow (e.g., .about.0.25 micrometer) gates which enhance transistor microwave cut-off frequency. Because these compound semiconductors resist chemical etchants, isolation is accomplished by etching with reactive ions to form an isolation mesa having a vertical mesa sidewall. To improve breakdown, the mesa sidewall is covered with a passivation layer prior to deposition of a gate feed that contacts the gate. To reduce parasitic gate capacitance, the gate feed is spaced from a narrow edge of the transistor's two-dimensional electron gas.