Abstract: A semiconductor device including a gate electrode formed over a first region of a semiconductor substrate of a first conduction type; a source region and a drain region of the first conduction type formed on both sides of the gate electrode; a channel dope layer of a second conduction type formed in at least a region on a side of the source region of a channel region, the channel dope layer having a concentration gradient of a concentration of a dopant impurity of the second conduction type, which decrease toward the drain region; a first well of the second conduction type having a concentration gradient of a concentration of a dopant impurity of the second conduction type, which decrease toward the drain region; and a second well of the second conduction type formed in the first region, connected to the first well and positioned below the first well.

Abstract: According to an exemplary embodiment, a MOS transistor, such as an LDMOS transistor, includes a gate having a first side situated immediately adjacent to at least one source region and at least one body tie region. The MOS transistor further includes a drain region spaced apart from a second side of the gate. The MOS transistor further includes a body region in contact with the at least one body tie region, where the at least one body tie region is electrically connected to the at least one source region. The MOS transistor further includes a lightly doped region separating the drain region from the second side of the gate. The lightly doped region can isolate the body region from an underlying substrate.

Abstract: A semiconductor device for a high voltage application includes a doped source base region, an N+ source region, a P+ source region and a gate structure. The doped source base region has P-type. The N+ source region extends downwards into the doped source base region. The P+ source region is close to the N+ source region, extends downwards into the doped source base region, and is doped heavier than the doped source base region. The gate structure is coupled to the N+ source region and is near to the P+ source region.

Abstract: A semiconductor device and methods for forming the same are provided. The semiconductor device includes a first doped region and a second, oppositely doped, region both formed in a substrate, a first gate formed overlying a portion of the first doped region and a portion of the second doped region, two or more second gates formed over the substrate overlying a different portion of the second doped region, one or more third doped regions in the second doped region disposed only between the two or more second gates such that the third doped region and the second doped region having opposite conductivity types, a source region in the first doped region, and a drain region in the second doped region disposed across the second gates from the first gate.

Abstract: A semiconductor structure includes a semiconductor substrate, formed on which are a first layer and a second layer, and an alignment-control mask. The alignment-control mask includes a first direction reference element, formed in a first region of the first layer and extending in a first alignment direction, and first position reference elements, formed in a first region of the second layer that corresponds to the first region of the first layer accommodating the first direction reference element. The first position reference elements are arranged in succession in the first alignment direction and in respective staggered positions with respect to a second alignment direction perpendicular to the first alignment direction.

Abstract: A structure, method and system for complementary strain fill for integrated circuit chips. The structure includes a first region of an integrated circuit having multiplicity of n-channel and p-channel field effect transistors (FETs); a first stressed layer over n-channel field effect transistors (NFETs) of the first region, the first stressed layer of a first stress type; a second stressed layer over p-channel field effect transistors (PFETs) of the first region, the second stressed layer of a second stress type, the second stress type opposite from the first stress type; and a second region of the integrated circuit, the second region not containing FETs, the second region containing first sub-regions of the first stressed layer and second sub-regions of the second stressed layer.

Abstract: A common cut mask is employed to define a gate pattern and a local interconnect pattern so that local interconnect structures and gate structures are formed with zero overlay variation relative to one another. A local interconnect structure may be laterally spaced from a gate structure in a first horizontal direction, and contact another gate structure in a second horizontal direction that is different from the first horizontal direction. Further, a gate structure may be formed to be collinear with a local interconnect structure that adjoins the gate structure. The local interconnect structures and the gate structures are formed by a common damascene processing step so that the top surfaces of the gate structures and the local interconnect structures are coplanar with each other.

Abstract: This disclosure relates to devices and methods relating to coupled first and second device portions.

Abstract: A lateral-diffusion metal-oxide-semiconductor device includes a semiconductor substrate having at least a field oxide layer, a gate having a layout pattern of a racetrack shape formed on the substrate, a common source formed in the semiconductor substrate and enclosed by the gate, and a drain surrounding the gate and formed in the semiconductor substrate. The gate covers a portion of the field oxide layer. The common source includes a first doped region having a first conductive type and a plurality of islanding second doped regions having a second conductive type. The drain includes a third doped region having the first conductive type. The third doped region overlaps a portion of the field oxide layer and having an overlapping area between the third doped region and the field oxide layer.

Abstract: In one aspect, a semiconductor device includes a semiconductor substrate; and a transistor element including a parallel structure of a first-conductivity-type drift region and a second-conductivity-type column region, and a second-conductivity-type base region, the transistor element being formed on the semiconductor substrate. An outer peripheral region located outside an element forming region has a parallel structure of a first-conductivity-type drift region and a second-conductivity-type column region, and a second-conductivity-type annular diffusion region which is formed at a side of the base region and which is spaced apart from the base region. An innermost end and a neighboring portion thereof of the annular diffusion region are located on the column region, and an outermost end of the annular diffusion region is located outside an outermost peripheral column region. A field insulating film that covers the annular diffusion region is stacked on the semiconductor layer in the outer peripheral region.

Abstract: A method to form a LDMOS transistor includes forming a gate/source/body opening and a drain opening in a field oxide on a substrate structure, forming a gate oxide in the gate/source/body opening, and forming a polysilicon layer over the substrate structure. The polysilicon layer is anisotropically etched to form polysilicon spacer gates separated by a space in the gate/source/body opening and a polysilicon drain contact in the drain opening. A body region is formed self-aligned about outer edges of the polysilicon spacer gates, a source region is formed self-aligned about inner edges of the polysilicon spacer gates, and a drain region is formed under the polysilicon drain contact and self-aligned with respect to the polysilicon spacer gates. A drift region forms in the substrate structure between the body region and the drain region, and a channel region forms in the body region between the source region and the drift region.

Abstract: In a method for producing a thyristor, first and second connection regions are formed on or above a substrate; the first connection region is doped with dopant atoms of a first conductivity type and the second connection region is doped with dopant atoms of a second conductivity type; first and second body regions are formed between the connection regions, wherein the first body region is formed between the first connection region and second body region, and the second body region is formed between the first body region and second connection region; the first body region is doped with dopant atoms of the second conductivity type and the second body region is doped with dopant atoms of the first conductivity type, wherein the dopant atoms are in each case introduced into the respective body region using a Vt implantation method; a gate region is formed on or above the body regions.

Abstract: A method of forming a semiconductor device comprises forming a control electrode over a portion of a semiconductor layer, forming recesses extending into the semiconductor layer on opposing sides of the control electrode, and forming doped regions in the semiconductor layer through the recesses. The doped regions form current electrode regions of the semiconductor device and each doped region extends into the semiconductor layer from at least a base of a recess. The method further comprises forming, after forming the doped regions, strained semiconductor regions in the recesses, wherein a junction between each doped region and the semiconductor layer is formed below an interface between a strained semiconductor region and the semiconductor layer.

Abstract: An object of the present invention is to reduce the influence of a foreign substance adhering to a single crystalline semiconductor substrate and manufacture a semiconductor substrate with a high yield. Another object of the present invention is to manufacture, with a high yield, a semiconductor device which has stable characteristics. In the process of manufacturing a semiconductor substrate, when an embrittled region is to be formed in a single crystalline semiconductor substrate, the surface of the single crystalline semiconductor substrate is irradiated with hydrogen ions from oblique directions at multiple (at least two) different angles, thereby allowing the influence of a foreign substance adhering to the single crystalline semiconductor substrate to be reduced and allowing a semiconductor substrate including a uniform single crystalline semiconductor layer to be manufactured with a high yield.

Abstract: A semiconductor device is provided which includes a semiconductor substrate, a gate structure formed on the substrate, sidewall spacers formed on each side of the gate structure, a source and a drain formed in the substrate on either side of the gate structure, the source and drain having a first type of conductivity, a lightly doped region formed in the substrate and aligned with a side of the gate structure, the lightly doped region having the first type of conductivity, and a barrier region formed in the substrate and adjacent the drain. The barrier region is formed by doping a dopant of a second type of conductivity different from the first type of conductivity.

Abstract: A sinker layer is in contact with a first conductivity-type well, and is separated from a first conductivity-type collector layer and a second conductivity-type drift layer. A second conductivity-type diffusion layer (second second-conductivity-type high-concentration diffusion layer) is formed in the surface layer of the sinker layer. The second conductivity-type diffusion layer has a higher impurity concentration than that of the sinker layer. The second conductivity-type diffusion layer and the first conductivity-type collector layer are isolated from each other with an element isolation insulating film interposed therebetween.

Abstract: Horizontal and vertical tunneling field-effect transistors (TFETs) having an abrupt junction between source and drain regions increases probability of direct tunneling of carriers (e.g., electrons and holes). The increased probability allows a higher achievable on current in TFETs having the abrupt junction. The abrupt junction may be formed by placement of a dielectric layer or a dielectric layer and a semiconductor layer in a current path between the source and drain regions. The dielectric layer may be a low permittivity oxide such as silicon oxide, lanthanum oxide, zirconium oxide, or aluminum oxide.

Abstract: A DMOS on SOI transistor including an elongated gate extending across the entire width of an active area; a drain region of a first conductivity type extending across the entire width of the active area; a source region of the first conductivity type extending parallel to the gate and stopping before the limit of the active area at least on one side of the transistor width, an interval existing between the limit of the source region and the limit of the active area; a bulk region of a second conductivity type extending under the gate and in said interval; a more heavily-doped region of the second conductivity type extending on a portion of said interval on the side of the limit of the active area; and an elongated source metallization extending across the entire width of the active area.

Abstract: A semiconductor device includes: a semiconductor substrate; a silicon pillar provided perpendicularly to a main surface of the semiconductor substrate; a gate dielectric film that covers a portion of a side surface of the silicon pillar; an insulator pillar that covers remaining portions of the side surface of the silicon pillar; a gate electrode that covers the silicon pillar via the gate dielectric film and the insulator pillar; an interlayer dielectric film provided above the silicon pillar, the gate dielectric film, the insulator pillar, and the gate electrode; and a gate contact plug embedded in a contact hole provided in the interlayer dielectric film, and in contact with the gate electrode and the insulator pillar. A film thickness of the insulator pillar in a lateral direction is thicker than a film thickness of the gate dielectric film in a lateral direction.

Abstract: A semiconductor device including a first conductive epitaxial layer, a second conductive type first well provided in the first conductive epitaxial layer, a first conductive body provided in the first conductive epitaxial layer, a second conductive type drain extension region provided in the first conductive epitaxial layer and interposed between the first conductive body and the second conductive type first well, a second conductive type second well provided in the second conductive type first well, and a gate provided in the first conductive epitaxial layer.

Abstract: Insulated-gate field-effect transistors (“IGFETs”), both symmetric and asymmetric, suitable for a semiconductor fabrication platform that provides IGFETs for analog and digital applications, including mixed-signal applications, utilize empty-well regions in achieving high performance. A relatively small amount of semiconductor well dopant is near the top of each empty well. Each IGFET (100, 102, 112, 114, 124, or 126) has a pair of source/drain zones laterally separated by a channel zone of body material of the empty well (180, 182, 192, 194, 204, or 206). A gate electrode overlies a gate dielectric layer above the channel zone. Each source/drain zone (240, 242, 280, 282, 520, 522, 550, 552, 720, 722, 752, or 752) has a main portion (240M, 242M, 280M, 282M, 520M, 522M, 550M, 552M, 720M, 722M, 752M, or 752M) and a more lightly doped lateral extension (240E, 242E, 280E, 282E, 520E, 522E, 550E, 552E, 720E, 722E, 752E, or 752E).

Abstract: A semiconductor device has: a low concentration drain region creeping under a gate electrode of a MIS type transistor; a high concentration drain region having an impurity concentration higher than the low concentration drain region and formed in the low concentration drain region spaced apart from the gate electrode; and an opposite conductivity type region of a conductivity type opposite to the drain region formed in the low concentration drain region on a surface area between the high concentration drain region and the gate electrode, the opposite conductivity type region and low concentration drain region forming a pn junction.

Abstract: A MOS transistor comprising a conductive extension of its source region, insulated from its substrate, and partially extending under its channel.

Abstract: Provided is a manufacturing method for an offset MOS transistor capable of operating safely even under a voltage of 50 V or higher. In the offset MOS transistor which includes a LOCOS oxide film, the LOCOS oxide film formed in a periphery of a drain diffusion layer, in which a high withstanding voltage is required, is etched, and the drain diffusion layer is formed so as to spread into a surface region of a semiconductor substrate located below a region in which the LOCOS oxide film is thinned. As a result, end portions of the drain diffusion layer are covered by an offset diffusion layer, whereby electric field concentration occurring in a region of a lower portion of the drain diffusion layer can be relaxed.

Abstract: Provided are a high voltage semiconductor device in which a field shaping layer is formed on the entire surface of a semiconductor substrate and a method of fabricating the same. Specifically, the high voltage semiconductor device includes a first conductivity-type semiconductor substrate. A second conductivity-type semiconductor layer is disposed on a surface of the semiconductor substrate, and a first conductivity-type body region is formed in semiconductor layer. A second conductivity-type source region is formed in the body region. A drain region is formed in the semiconductor layer and is separated from the body region. The field shaping layer is formed on the entire surface of the semiconductor layer facing the semiconductor layer.

Abstract: Circuits and methods for providing a dual gate oxide (DGO) embedded SRAM with additional logic portions, where the logic and the embedded SRAM have NMOS transistors having a common gate dielectric thickness but have different lightly doped drain (LDD) implantations formed using different LDD masks to provide optimum transistor operation. In an embodiment, a first embedded SRAM is a single port device and a second embedded SRAM is a dual port device having a separate read port. In certain embodiments, the second SRAM includes NMOS transistors having LDD implants formed using the logic portion LDD mask. Transistors formed with the logic portion LDD mask are faster and have lower Vt than transistors formed using a SRAM LDD mask. Dual core devices having multiple embedded SRAM arrays are disclosed. Methods for making the embedded SRAM are also disclosed.

Abstract: An insulated-gate field-effect transistor (100, 100V, 140, 150, 150V, 160, 170, 170V, 180, 180V, 190, 210, 210W, 220, 220U, 220V, 220W, 380, or 480) has a hypoabrupt vertical dopant profile below one (104 or 264) of its source/drain zones for reducing the parasitic capacitance along the pn junction between that source/drain zone and adjoining body material (108 or 268). In particular, the concentration of semiconductor dopant which defines the conductivity type of the body material increases by at least a factor of 10 in moving from that source/drain zone down to an underlying body-material location no more than 10 times deeper below the upper semiconductor surface than that source/drain zone. The body material preferably includes a more heavily doped pocket portion (120 or 280) situated along the other source/drain zone (102 or 262).

Abstract: Method and apparatus for providing a lateral double-diffused MOSFET (LDMOS) transistor having a dual gate. The dual gate includes a first gate and a second gate. The first gate includes a first oxide layer formed over a substrate, and the second gate includes a second oxide layer formed over the substrate. The first gate is located a pre-determined distance from the second gate. A digitally implemented voltage regulator is also provided that includes a switching circuit having a dual gate LDMOS transistor.

Abstract: The present disclosure discloses a lateral DMOS with recessed source contact and method for making the same. The lateral DMOS comprises a recessed source contact which has a portion recessed into a source region to reach a body region of the lateral DMOS. The lateral DMOS according to various embodiments of the present invention may have greatly reduced size and may be cost saving for fabrication.

Abstract: An LDPMOS structure having enhanced breakdown voltage and specific on-resistance is described, as is a method for fabricating the structure. A P-field implanted layer formed in a drift region of the structure and surrounding a tightly doped drain region effectively increases breakdown voltage while maintaining a relatively low specific on-resistance.

Abstract: Provided is a semiconductor device including an n-type metal oxide semiconductor transistor for electrostatic discharge protection including drain regions and source regions placed alternately with each other, and gate electrodes each placed between each of the drain regions and each of the source regions, in which: the first metal interconnects formed on the source regions are electrically connected to the second metal interconnect through constant size via-holes, and a ratio between the numbers of the via-holes arranged above each of the source regions is controlled to be less than four according to a distance from the ground potential supply line.

Abstract: A method and circuit in which the drive strength of a FinFET transistor can be selectively modified, and in particular can be selectively reduced, by omitting the LDD extension formation in the source and/or in the drain of the FinFET. One application of this approach is to enable differentiation of the drive strengths of transistors in an integrated circuit by applying the technique to some, but not all, of the transistors in the integrated circuit. In particular in a SRAM cell formed from FinFET transistors the application of the technique to the pass-gate transistors, which leads to a reduction of the drive strength of the pass-gate transistors relative to the drive strength of the pull-up and pull-down transistors, results in improved SRAM cell performance.

Abstract: A non-volatile semiconductor memory device according to an embodiment includes: a p-type semiconductor substrate; a p-type first p well which is formed in the semiconductor substrate and in which a bit line connecting transistor configured to connect a bit line of a memory cell and a sense amplifier unit is formed; and an n-type first N well which surrounds the first P well and which is configured to electrically isolate the first P well from the semiconductor substrate.

Abstract: According to one embodiment, a semiconductor device includes a drain region, a source region, a channel region, an insulating film, a gate electrode, a first semiconductor region, and a second semiconductor region. The source region includes a source layer of the first conductivity type, a first back gate layer of the second conductivity type, and a second back gate layer of the second conductivity type. The first back gate layer is adjacent to the second semiconductor region on one side in a channel length direction, and is adjacent to the source layer on one other side in the channel length direction. The second back gate layer is adjacent to the source layer on the one side in the channel length direction, and is adjacent to the second semiconductor region on the one other side in the channel length direction.

Abstract: The present invention discloses a SOI MOS device having BTS structure and manufacturing method thereof. The source region of the SOI MOS device comprises: two heavily doped N-type regions, a heavily doped P-type region formed between the two heavily doped N-type regions, a silicide formed above the heavily doped N-type regions and the heavily doped P-type region, and a shallow N-type region which is contact to the silicide; an ohmic contact is formed between the heavily doped P-type region and the silicide thereon to release the holes accumulated in body region of the SOI MOS device and eliminate floating body effects thereof without increasing the chip area and also overcome the disadvantages such as decreased effective channel width of the devices in the BTS structure of the prior art.

Abstract: A LDMOS transistor is implemented in a first impurity region on a substrate. The LDMOS transistor has a source that includes a second impurity region. The second impurity region is implanted into the surface of the substrate within the first impurity region. Additionally, the LDMOS transistor has a drain that includes a third impurity region. The third impurity region is implanted into the surface of the substrate within the first impurity region. The third impurity region is spaced a predetermined distance away from a gate of the LDMOS transistor. The drain of the LDMOS transistor further includes a fourth impurity region within the third impurity region. The fourth impurity region provides an ohmic contact for the drain.

Abstract: A laterally double diffused metal oxide semiconductor device includes a well region having a first conductivity, a first carrier redistribution region having the first conductivity type, wherein the second well region is under the well region, and a highly doped buried layer under the second well region. The highly doped buried layer has the first conductivity type and has a dopant concentration less than that of the well region and less than that of the first carrier redistribution region, and the buried layer is tied to the first well region. In addition, a method for forming the laterally double diffused metal oxide semiconductor device, which may use epitaxial growth, is disclosed.

Abstract: According to an exemplary embodiment, a method for fabricating a MOS transistor, such as an LDMOS transistor, includes forming a self-aligned lightly doped region in a first well underlying a first sidewall of a gate. The method further includes forming a self-aligned extension region under a second sidewall of the gate, where the self-aligned extension region extends into the first well from a second well. The method further includes forming a drain region spaced apart from the second sidewall of the gate. The method further includes forming a source region in the self-aligned lightly doped region and the first well. The self-aligned lightly doped region and the self-aligned extension region define a channel length of the MOS transistor, such as an LDMOS transistor.

Abstract: An Electro-Static Discharge (ESD) protection device is provided. The ESD protection device includes a metal-oxide semiconductor (MOS) transistor, including a source area having a surface on which a first silicide is formed, the source area including a source connecting area including a first connecting portion formed on the first silicide, and a source extension area, a gate arranged in parallel with the source area, and a drain area arranged in parallel with the source area and the gate, the drain area having a surface on which a second silicide is formed, the drain area including a drain connecting area formed opposite the source extension area, the drain connecting area including second connection portion formed on the second silicide, and a drain extension area formed opposite the source connecting area.

Abstract: In sophisticated semiconductor devices, a strain-inducing semiconductor alloy may be positioned close to the channel region by forming cavities on the basis of a wet chemical etch process, which may have an anisotropic etch behavior with respect to different crystallographic orientations. In one embodiment, TMAH may be used which exhibits, in addition to the anisotropic etch behavior, a high etch selectivity with respect to silicon dioxide, thereby enabling extremely thin etch stop layers which additionally provide the possibility of further reducing the offset from the channel region while not unduly contributing to overall process variability.

Abstract: First example embodiments comprise forming a stress layer over a MOS transistor (such as a LDMOS Tx) comprised of a channel and first, second and third junction regions. The stress layer creates a stress in the channel and the second junction region of the Tx. Second example embodiments comprise forming a MOS FET and at least a dummy gate over a substrate. The MOS is comprised of a gate, channel, source, drain and offset drain. At least one dummy gate is over the offset drain. A stress layer is formed over the MOS and the dummy gate. The stress layer and the dummy gate improve the stress in the channel and offset drain region.

Abstract: A semiconductor device and its manufacturing method are disclosed. The semiconductor device comprises a gate, and source and drain regions on opposite sides of the gate, wherein a portion of a gate dielectric layer located above the channel region is thinner than a portion of the gate dielectric layer located at the overlap region of the drain and the gate. The thicker first thickness portion may ensure that the device can endure a higher voltage at the drain to gate region, while the thinner second thickness portion may ensure excellent performance of the device.

Abstract: An apparatus is disclosed to increase a breakdown voltage of a semiconductor device. The semiconductor device can include a modified breakdown shallow trench isolation (STI) region to effectively reduce its drain to source resistance when compared to a conventional semiconductor device. This reduction in the drain to source resistance increases the breakdown voltage of the semiconductor device when compared to the conventional semiconductor device by allowing more current to pass from a source region to a drain region of the semiconductor device. The semiconductor device can include a modified well region to reduce its drain to source resistance. The modified well region allows more current to pass from a source region to a drain region of the semiconductor device, thereby further increasing the break down voltage of the semiconductor device from that of the conventional semiconductor device.

Abstract: A lateral device includes a gate region connected to a drain region by a drift layer. An insulation region adjoins the drift layer between the gate region and the drain region. Permanent charges are embedded in the insulation region, sufficient to cause inversion in the insulation region.

Abstract: A DMOS transistor is fabricated with its source/body/deep body regions formed on the walls of a first set of trenches, and its drain regions formed on the walls of a different set of trenches. A gate region that is formed in a yet another set of trenches can be biased to allow carriers to flow from the source to the drain. Lateral current low from source/body regions on trench walls increases the active channel perimeter to a value well above the amount that would be present if the device was fabricated on just the surface of the wafer. Masking is avoided while open trenches are present. A transistor with a very low on-resistance per unit area is obtained.

Abstract: An integrated circuit with a transistor advantageously embodied in a laterally diffused metal oxide semiconductor device having a gate located over a channel region recessed into a semiconductor substrate and a method of forming the same. In one embodiment, the transistor includes a source/drain including a lightly or heavily doped region adjacent the channel region, and an oppositely doped well extending under the channel region and a portion of the lightly or heavily doped region of the source/drain. The transistor also includes a channel extension, within the oppositely doped well, under the channel region and extending under a portion of the lightly or heavily doped region of the source/drain.

Abstract: A power semiconductor device that realizes high-speed turnoff and soft switching at the same time has an n-type main semiconductor layer that includes lightly doped n-type semiconductor layers and extremely lightly doped n-type semiconductor layers arranged alternately and repeatedly between a p-type channel layer and an n+-type field stop layer, in a direction parallel to the first major surface of the n-type main semiconductor layer. A substrate used for manufacturing the semiconductor device is fabricated by forming trenches in an n-type main semiconductor layer 1 and performing ion implantation and subsequent heat treatment to form an n+-type field stop layer in the bottom of the trenches. The trenches are then filled with a semiconductor doped more lightly than the n-type main semiconductor layer for forming extremely lightly doped n-type semiconductor layers. The manufacturing method is applicable with variations to various power semiconductor devices such as IGBT's, MOSFET's and PIN diodes.

Abstract: Devices, structures, and related methods for IGBTs and the like which include a self-aligned series resistance at the source-body junction to avoid latchup. The series resistance is achieved by using a charged dielectric, and/or by using a dielectric which provides a source of dopant atoms of the same conductivity type as the source region, at a sidewall adjacent to the source region.

Abstract: The present disclosure provides a semiconductor device having a transistor. The transistor includes a substrate and first and second wells that are disposed within the substrate. The first and second wells are doped with different types of dopants. The transistor includes a first gate that is disposed at least partially over the first well. The transistor further includes a second gate that is disposed over the second well. The transistor also includes source and drain regions. The source and drain regions are disposed in the first and second wells, respectively. The source and drain regions are doped with dopants of a same type.

Abstract: An IGFET (40 or 42) has a channel zone (64 or 84) situated in body material (50). Short-channel threshold voltage roll-off and punchthrough are alleviated by arranging for the net dopant concentration in the channel zone to longitudinally reach a local surface minimum at a location between the IGFET's source/drain zones (60 and 62 or 80 and 82) and by arranging for the net dopant concentration in the body material to reach a local subsurface maximum more than 0.1 ?m deep into the body material but not more than 0.1 ?m deep into the body material. The source/drain zones (140 and 142 or 160 and 162) of a p-channel IGFET (120 or 122) are provided with graded-junction characteristics to reduce junction capacitance, thereby increasing switching speed.