Abstract: A system for manufacturing a semiconductor device that has a gate electrode and a pair of diffusion layers formed in a semiconductor substrate on sides of the gate electrode, the system including structure for forming an insulating film and a gate electrode on a semiconductor substrate, obtaining a thickness of an affected layer formed in a surface of the semiconductor substrate, forming a pair of diffusion layers by injecting an impurity element into the semiconductor substrate in areas flanking the gate electrodes based on a predetermined injection parameter, performing activating heat treatment based on a predetermined heat treatment parameter, and deriving the injection parameter or heat treatment parameter in response to the obtained thickness of the affected layer such that the diffusion layers are set to a predetermined sheet resistance.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs). The devices have raised regions with sloped sidewalls which taper inward. The sidewalls can form an angle of 5° or more from vertical to the substrate surface. The devices can have dual-sloped sidewalls in which a lower portion of the sidewalls forms an angle of 5° or more from vertical and an upper portion of the sidewalls forms an angle of <5° from vertical. The devices can be made using normal (i.e., 0°) or near normal incident ion implantation. The devices have relatively uniform sidewall doping and can be made without angled implantation.

Abstract: The invention is related to a semiconductor device with alternately arranged P-type and N-type thin semiconductor layers and method for manufacturing the same. For P-type device, the method includes trench formation, thermal oxide formation on trench sidewalls, N-type silicon formation in trenches, N-type impurity diffusion through thermal oxide into P-type epitaxial layer, oxidation of N-type silicon in trenches and oxide removal. In the semiconductor device, N-type thin semiconductor layers are formed by N-type impurity diffusion through oxide to P-type epitaxial layers, and trenches are filled with oxide. With this method, relatively low concentration impurity in high voltage device can be realized by current mass production process, and the device development cost and manufacturing cost are decreased.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs) or diodes such as junction barrier Schottky (JBS) diodes or PiN diodes. The devices have graded p-type semiconductor layers and/or regions formed by epitaxial growth. The methods do not require ion implantation. The devices can be made from a wide-bandgap semiconductor material such as silicon carbide (SiC) and can be used in high temperature and high power applications.

Abstract: A junction gate field-effect transistor (JFET) for an integrated circuit (IC) chip is provided comprising a source region, a drain region, a lower gate, and a channel, with an insulating shallow trench isolation (STI) region extending from an inner edge of an upper surface of the source region to an inner edge of an upper surface of the drain region, without an intentionally doped region, e.g., an upper gate, coplanar with an upper surface of the IC chip between the source/drain regions. In addition, an asymmetrical quasi-buried upper gate can be included, disposed under a portion of the STI region, but not extending under a portion of the STI region proximate to the drain region. Embodiments of this invention also include providing an implantation layer, under the source region, to reduce Ron. A related method and design structure are also disclosed.

Abstract: A method for manufacturing a semiconductor device including a vertical double-diffusedmetal-oxide-semiconductor (VDMOS) transistor includes preparing a semiconductor substrate and injecting a first impurity of a second conductivity type to a first region, injecting a second impurity to a second region that is located inside and is narrower than the first region, and forming an epitaxial layer on the semiconductor substrate and forming the semiconductor layer constituted by the semiconductor substrate and the epitaxial layer, and at a same time, diffusing the first and the second impurities injected in a first impurity injection and a second impurity injection to form a buried layer of the second conductivity type.

Abstract: Methods are provided for fabricating a semiconductor device. A method comprises forming a layer of a first semiconductor material overlying the bulk substrate and forming a layer of a second semiconductor material overlying the layer of the first semiconductor material. The method further comprises creating a fin pattern mask on the layer of the second semiconductor material and anisotropically etching the layer of the second semiconductor material and the layer of the first semiconductor material using the fin pattern mask as an etch mask. The anisotropic etching results in a fin formed from the second semiconductor material and an exposed region of first semiconductor material underlying the fin. The method further comprises forming an isolation layer in the exposed region of first semiconductor material underlying the fin.

Abstract: A semiconductor device as described herein includes a body region of a first conductivity type adjoining a channel region of a second conductivity at a first side of the channel region. A gate control region of the first conductivity type adjoins the channel region at a second side of the channel region opposed to the first side, the channel region being configured to be controlled in its conductivity by voltage application between the gate control region and the body region. A source zone of the second conductivity type is arranged within the body region and a channel stop zone of the second conductivity type is arranged at the first side, the channel stop zone being arranged at least partly within at least one of the body region and the channel region. The channel stop zone includes a maximum concentration of dopants lower than a maximum concentration of dopants of the source zone.

Abstract: A method for fabricating a vertical channel transistor includes forming a structure including a plurality of trimmed pillar patterns, forming a conductive layer for a gate electrode including a seam over a resultant structure with the pillar patterns, performing an etch-back process until the seam is exposed, and forming a gate electrode by etching the etch-backed conductive layer.

Abstract: A vertical junction field effect transistor (VJFET) having a self-aligned pin, a p+/n/n+ or a p+/p/n+ gate-source junction is described. The device gate can be self-aligned to within 0.5 ?m to the source in order to maintain good high voltage performance (i.e. low DIBL) while reducing gate-source junction leakage under reverse bias. The device can be a wide-bandgap semiconductor device such as a SiC vertical channel junction field effect. Methods of making the device are also described.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs). The devices have raised regions with sloped sidewalls which taper inward. The sidewalls can form an angle of 5° or more from vertical to the substrate surface. The devices can have dual-sloped sidewalls in which a lower portion of the sidewalls forms an angle of 5° or more from vertical and an upper portion of the sidewalls forms an angle of <5° from vertical. The devices can be made using normal (i.e., 0°) or near normal incident ion implantation. The devices have relatively uniform sidewall doping and can be made without angled implantation.

Abstract: The leakage current generated in a pn junction region between a gate and a source is reduced in a junction FET using a silicon carbide substrate. In a trench junction FET using a silicon carbide substrate, nitrogen is introduced into a sidewall and a bottom surface of a trench, thereby forming an n type layer and an n+ type layer on a surface of the trench. In this manner, the pn junction region corresponding to the junction region between a p+ type gate region and an n+ type source region is exposed on a main surface of a semiconductor substrate instead of on the damaged sidewall of the trench, and also the exposed region thereof is narrowed. Accordingly, the leakage current in the pn junction region can be reduced.

Abstract: Semiconductor devices are described wherein current flow in the device is confined between the rectifying junctions (e.g., p-n junctions or metal-semiconductor junctions). The device provides non-punch-through behavior and enhanced current conduction capability. The devices can be power semiconductor devices as such as Junction Field-Effect Transistors (VJFETs), Static Induction Transistors (SITs), Junction Field Effect Thyristors, or JFET current limiters. The devices can be made in wide bandgap semiconductors such as silicon carbide (SiC). According to some embodiments, the device can be a normally-off SiC vertical junction field effect transistor. Methods of making the devices and circuits comprising the devices are also described.

Abstract: A semiconductor device with inherent capacitances and method for its production. The semiconductor device has an inherent feedback capacitance between a control electrode and a first electrode. In addition, the semiconductor device has an inherent drain-source capacitance between the first electrode and a second electrode. At least one monolithically integrated additional capacitance is connected in parallel to the inherent feedback capacitance or in parallel to the inherent drain-source capacitance. The additional capacitance comprises a first capacitor surface and a second capacitor surface opposite the first capacitor surface. The capacitor surfaces are structured conductive layers of the semiconductor device on a front side of the semiconductor body, between which a dielectric layer is located and which form at least one additional capacitor.

Abstract: A semiconductor device includes: a substrate; and depletion and enhancement mode JFETs. The depletion mode JFET includes: a concavity on the substrate; a channel layer in the concavity; a first gate region on the channel layer; first source and drain regions on respective sides of the first gate region in the channel layer; first gate, source and drain electrodes. The enhancement mode JFET includes: a convexity on the substrate; the channel layer on the convexity; a second gate region on the channel layer; second source and drain regions on respective sides of the second gate region in the channel layer; second gate, source and drain electrodes. A thickness of the channel layer in the concavity is larger than a thickness of the channel layer on the convexity.

Abstract: A silicon carbide semiconductor device having a JFET or a MOSFET includes a semiconductor substrate and a trench. The semiconductor substrate has a silicon carbide substrate, a drift layer on the silicon carbide substrate, a first gate region on the drift layer, and a source region on the first gate region. The trench has a strip shape with a longitudinal direction and reaches the drift layer by penetrating the source region and the first gate region. The trench is filled with a channel layer and a second gate region on the channel layer. The source region is not located at an end portion of the trench in the longitudinal direction.

Abstract: A wide band gap semiconductor device having a JFET, a MESFET, or a MOSFET mainly includes a semiconductor substrate, a first conductivity type semiconductor layer, and a first conductivity type channel layer. The semiconductor layer is formed on a main surface of the substrate. A recess is formed in the semiconductor layer in such a manner that the semiconductor layer is divided into a source region and a drain region. The recess has a bottom defined by the main surface of the substrate and a side wall defined by the semiconductor layer. The channel layer has an impurity concentration lower than an impurity concentration of the semiconductor layer. The channel layer is formed on the bottom and the side wall of the recess by epitaxial growth.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs) or diodes such as junction barrier Schottky (JBS) diodes or PiN diodes. The devices are made using selective ion implantation using an implantation mask. The devices have implanted sidewalls formed by scattering of normal or near normal incident ions from the implantation mask. Vertical junction field-effect transistors with long channel length are also described. The devices can be made from a wide-bandgap semiconductor material such as silicon carbide (SiC) and can be used in high temperature and high power applications.

Abstract: A lateral super junction JFET is formed from stacked alternating P type and N type semiconductor layers over a P-epi layer supported on an N+ substrate. An N+ drain column extends down through the super junction structure and the P-epi to connect to the N+ substrate to make the device a bottom drain device. N+ source column and P+ gate column extend through the super junction but stop at the P-epi layer. A gate-drain avalanche clamp diode is formed from the bottom the P+ gate column through the P-epi to the N+ drain substrate.

Abstract: The present invention relates to a semiconductor device, which includes a junction region formed in an active area of a semiconductor substrate; a trench defining a buried gate predetermined area within the semiconductor substrate; a gate electrode buried in an lower portion of the trench; an ion implantation region formed in a sidewall of the trench; and a capping insulation layer formed in an upper portion of the gate electrode.

Abstract: A vertical channel transistor includes a plurality of active pillar patterns extending perpendicularly from the top surface of the substrate toward an upper part. A gate insulating layer is deposited on the side wall of the active pillar pattern and serves as an ion diffusion barrier between the pillar patterns and surrounding lower gate electrodes. The resultant pillar pattern structure is encapsulated with a metal. The resultant pillar pattern is surrounded on all sides by a specified height by a sacrificial layer of Spin-On Dielectric (SOD). The metal layer is etched-back to the height of the sacrificial layer, thus forming the lower gate electrodes. A spacer layer of an insulating mater is deposited surrounding the upper part of the pillar patterns and the sacrificial layer is removed exposing a part of the lower gate electrodes. The exposed gate electrode is etched to facilitate semiconductor integration.

Abstract: A method for processing a substrate comprising at least a buried oxide (BOX) layer and a semiconductor material layer is provided. The method includes etching the semiconductor material layer to form a vertical semiconductor material structure overlying the BOX layer, leaving an exposed portion of the BOX layer. The method further includes exposing a top surface of the exposed portion of the BOX layer to an oxide etch resistant species to form a thin oxide etch resistant layer overlying the exposed portion of the BOX layer.

Abstract: A semiconductor device includes: a substrate; a first junction region and a second junction region formed separately from each other to a certain distance in the substrate; an etch barrier layer formed in the substrate underneath the first junction region; and a plurality of recess channels formed in the substrate between the first junction region and the second junction region.

Abstract: Methods include, for example, forming a vertically disposed active region on a substrate; forming a first gate over a portion of the vertically disposed active region; forming a dielectric over the portion; exposing an upper surface of the first gate; forming a second gate over the upper surface; and forming a spacer pocket region between the vertically disposed active region, the first gate and the dielectric, wherein the spacer pocket region is self-aligned to a lower surface of the second gate and has a substantially uniform thickness from an upper to a lower extent thereof.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs). The devices have raised regions with sloped sidewalls which taper inward. The sidewalls can form an angle of 5° or more from vertical to the substrate surface. The devices can have dual-sloped sidewalls in which a lower portion of the sidewalls forms an angle of 5° or more from vertical and an upper portion of the sidewalls forms an angle of <5° from vertical. The devices can be made using normal (i.e., 0°) or near normal incident ion implantation. The devices have relatively uniform sidewall doping and can be made without angled implantation.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs) or diodes such as junction barrier Schottky (JBS) diodes or PiN diodes. The devices have graded p-type semiconductor layers and/or regions formed by epitaxial growth. The methods do not require ion implantation. The devices can be made from a wide-bandgap semiconductor material such as silicon carbide (SiC) and can be used in high temperature and high power applications.

Abstract: Therefore, disclosed above are embodiments of a multi-fin field effect transistor structure (e.g., a multi-fin dual-gate FET or tri-gate FET) that provides low resistance strapping of the source/drain regions of the fins, while also maintaining low capacitance to the gate by raising the level of the straps above the level of the gate. Embodiments of the structure of the invention incorporate either conductive vias or taller source/drain regions in order to electrically connect the source/drain straps to the source/drain regions of each fin. Also, disclosed are embodiments of associated methods of forming these structures.

Abstract: A stack of a vertical fin and a planar semiconductor portion are formed on a buried insulator layer of a semiconductor-on-insulator substrate. A hybrid field effect transistor (FET) is formed which incorporates a finFET located on the vertical fin and a planar FET located on the planar semiconductor portion. The planar FET enables a continuous spectrum of on-current. The surfaces of the vertical fin and the planar semiconductor portion may be set to coincide with crystallographic orientations. Further, different crystallographic orientations may be selected for the surfaces of the vertical fin and the surfaces of the planar semiconductor portion to tailor the characteristics of the hybrid FET.

Abstract: The gate-all-around (GAA) type semiconductor device may include source/drain layers, a nanowire channel, a gate electrode and an insulation layer pattern. The source/drain layers may be disposed at a distance in a first direction on a semiconductor substrate. The nanowire channel may connect the source/drain layers. The gate electrode may extend in a second direction substantially perpendicular to the first direction. The gate electrode may have a height in a third direction substantially perpendicular to the first and second directions and may partially surround the nanowire channel. The insulation layer pattern may be formed between and around the source/drain layers on the semiconductor substrate and may cover the nanowire channel and a portion of the gate electrode. Thus, a size of the gate electrode may be reduced, and/or a gate induced drain leakage (GIDL) and/or a gate leakage current may be reduced.

Abstract: A trench MIS device is formed in a P-epitaxial layer that overlies an N-epitaxial layer and an N+ substrate. In one embodiment, the device includes an N-type drain-drift region that extends from the bottom of the trench to the N-epitaxial layer. Preferably, the drain-drift region is formed at least in part by fabricating spacers on the sidewalls of the trench and implanting an N-type dopant between the sidewall spacers and through the bottom of the trench. The drain-drift region can be doped more heavily than the conventional “drift region” that is formed in an N-epitaxial layer. Thus, the device has a low on-resistance. The device can be terminated by a plurality of polysilicon-filled termination trenches located near the edge of the die, with the polysilicon in each termination trench being connected to the mesa adjacent the termination trench.

Abstract: A method for making an integrated circuit including vertical junction field effect transistors is disclosed. One embodiment creates a vertical junction field effect transistor using a fault-tolerant or alignment-tolerant production process. The device performance is not harmed, even if misalignments in consecutive semiconductor processing steps occur.

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: A method for manufacturing a semiconductor device. The method includes providing a semiconductor body of a conductivity type, wherein the semiconductor body comprises a first surface. At least one buried region of a second conductivity type is formed in the semiconductor body and at least a surface region of the second conductivity type is formed at the first surface of the semiconductor body, wherein the buried region and the surface region are formed such that they are spaced apart from each other. The buried region is formed by deep implantation of a first dopant of the second conductivity type.

Abstract: Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs). The devices have raised regions with sloped sidewalls which taper inward. The sidewalls can form an angle of 5° or more from vertical to the substrate surface. The devices can have dual-sloped sidewalls in which a lower portion of the sidewalls forms an angle of 5° or more from vertical and an upper portion of the sidewalls forms an angle of <5° from vertical. The devices can be made using normal (i.e., 0°) or near normal incident ion implantation. The devices have relatively uniform sidewall doping and can be made without angled implantation.

Abstract: A method of manufacturing an insulated gate field effect transistor includes providing a substrate (2) having a low-doped region (4), forming insulated gate trenches (8) and implanting dopants of a first conductivity type at the base of the trenches (8). A body implant is implanted in the low-doped regions between the trenches; and diffused to form an insulated gate transistor structure in which the body implant diffuses to form a p-n junction between a body region (22) doped to have the second conductivity type above a drain region (20) doped to have the first conductivity type, the p-n junction being deeper below the first major surface between the trenches than at the trenches. The difference in doping concentration between the low-doped region (4) and the implanted region at the base of the trenches causes the difference in depth of the body-drain p-n junction formed in the diffusion step.

Abstract: A vertical type GaN series field effect transistor having excellent pinch-off characteristics is provided. A compound semiconductor device includes a conductive semiconductor substrate, a drain electrode formed on a bottom surface of the conductive semiconductor substrate, a current blocking layer formed on a top surface of the conductive semiconductor substrate, made of high resistance compound semiconductor or insulator, and having openings, an active layer of compound semiconductor burying the openings and extending on an upper surface of the current blocking layer, a gate electrode formed above the openings and above the active layer, and a source electrode formed laterally spaced from the gate electrode and formed above the active layer.

Abstract: A method and a layered heterostructure for forming high mobility Ge channel field effect transistors is described incorporating a plurality of semiconductor layers on a semiconductor substrate, and a channel structure of a compressively strained epitaxial Ge layer having a higher barrier or a deeper confining quantum well and having extremely high hole mobility for complementary MODFETs and MOSFETs. The invention overcomes the problem of a limited hole mobility due to alloy scattering for a p-channel device with only a single compressively strained SiGe channel layer. This invention further provides improvements in mobility and transconductance over deep submicron state-of-the art Si pMOSFETs in addition to having a broad temperature operation regime from above room temperature (425 K) down to cryogenic low temperatures (0.4 K) where at low temperatures even high device performances are achievable.

Abstract: A method of manufacturing a semiconductor device, which has a gate electrode and a pair of diffusion layers formed in a semiconductor substrate on sides of the gate electrode, includes forming an insulating film and a gate electrode on a semiconductor substrate, obtaining a thickness of an affected layer formed in a surface of the semiconductor substrate, forming a pair of diffusion layers by injecting an impurity element into the semiconductor substrate in areas flanking the gate electrodes based on a predetermined injection parameter, performing activating heat treatment based on a predetermined heat treatment parameter, and a parameter deriving step provided between the obtaining step and the diffusion layer forming step, the parameter deriving step deriving the injection parameter or heat treatment parameter in response to the obtained thickness of the affected layer such that the diffusion layers are set to a predetermined sheet resistance.

Abstract: A semiconductor device is formed by forming a gate region, including a gate oxide layer, and impurity diffusion regions on a semiconductor substrate, forming a barrier metal layer on the gate region and the impurity diffusion regions of the semiconductor substrate, forming a passivation layer at an interface between the semiconductor substrate and the gate oxide layer to remove defects of the gate oxide layer, and then performing a nitridation process to remove impurities from the semiconductor substrate.

Abstract: A semiconductor component with charge compensation structure has a semiconductor body having a drift path between two electrodes. The drift path has drift zones of a first conduction type, which provide a current path between the electrodes in the drift path, while charge compensation zones of a complementary conduction type constrict the current path of the drift path. For this purpose, the drift path has two alternately arranged, epitaxially grown diffusion zone types, the first drift zone type having monocrystalline semiconductor material on a monocrystalline substrate, and a second drift zone type having monocrystalline semiconductor material in a trench structure, with complementarily doped walls, the complementarily doped walls forming the charge compensation zones.

Abstract: Methods, devices, and systems integrating Fin-JFETs and Fin-MOSFETs are provided. One method embodiment includes forming at least on Fin-MOSFET on a substrate and forming at least on Fin-JFET on the substrate.

Abstract: A semiconductor component and method of making a semiconductor component. One embodiment provides a first metallization structure electrically coupled to charge compensation zones via an ohmic contact and to drift zones via a Schottky contact. A second metallization structure, which is arranged opposite the first metallization structure, is electrically coupled to the charge compensation zones via a Schottky contact and to drift zones via an ohmic contact.

Abstract: The invention is directed to a memory cell on a substrate having a plurality of shallow trench isolations form therein, wherein top surfaces of the shallow trench isolations are lower than a top surface of the substrate and the shallow trench isolations together define a vertical fin structure of the substrate. The memory comprises a straddle gate, a carrier trapping layer and at least two source/drain regions. The straddle gate is located on the substrate and straddles over the vertical fin structure. The carrier trapping layer is located between the straddle gate and the substrate. The source/drain regions are located in a portion of the vertical fin structure of the substrate exposed by the straddle gate.

Abstract: A semiconductor device with structured current spread region and method is disclosed. One embodiment provides a drift portion of a first conductivity type, a current spread portion of the first conductivity type and first portions of the first conductivity type. The current spread portion and the first portions are arranged in a first plane on the drift portion, wherein the current spread portion surrounds at least partially the first portions. The semiconductor body further includes spaced apart body regions of a second conductivity type which are arranged on the current spread portion. Further, the doping concentration of the current spread portion is higher than the doping concentrations of the drift portion and of the first portions.

Abstract: A method for making an integrated circuit including vertical junction field effect transistors is disclosed. One embodiment creates a vertical junction field effect transistor using a fault-tolerant or alignment-tolerant production process. The device performance is not harmed, even if misalignments in consecutive semiconductor processing steps occur.

Abstract: A semiconductor device includes a cylindrical main pillar that is formed on a substrate and of which a central axis is perpendicular to the surface of the substrate, source and drain diffused layers that are formed in a concentric shape centered on the central axis at upper and lower portions of the main pillar and made from a first-conduction-type material, a body layer that is formed at an intermediate portion of the main pillar sandwiched between the source and drain diffused layers and made from the first-conduction-type material, and a front gate electrode that is formed on a lateral face of the main pillar while placing a gate insulating film therebetween. Moreover, a back gate electrode made from a second-conduction-type material is formed in a pillar shape penetrating from an upper portion to a lower portion on an inner side of the main pillar.

Abstract: A semiconductor device includes a first field effect transistor including a source and a gate and disposed in a silicon carbide substrate; and a second field effect transistor including a drain and a gate and disposed in the substrate. The drain of the second field effect transistor connects to the source of the first field effect transistor. The gate of the second field effect transistor connects to the gate of the first field effect transistor.

Abstract: A method for manufacturing a junction semiconductor device having a drain region including a low-resistance layer of a first conductive type formed on one surface of a semiconductor crystal, a source region including a low-resistance layer of a first conductive type formed on the other surface of the semiconductor crystal, a gate region of a second conductive type formed on the periphery of the source region, a high-resistance layer of a first conductive type between the source region and the drain region, and a recombination-inhibiting semiconductor layer of a second conductive type provided in the vicinity of the surface of the semiconductor crystal between the gate region and the source region.

Abstract: A semiconductor device 100 includes an element-forming region having gate electrode 108 formed therein, and a circumferential region formed in the outer circumference of the element-forming region and having an element-isolating region 118 formed therein. On the main surface of the semiconductor substrate 101, there is formed a parallel pn layer having an N-type drift region 104 and P-type column regions 106 alternately arranged therein. In the circumferential region, there is formed a field electrode 120, but the field electrode 120 is not formed on the P-type column regions 106. The P-type column regions 106 in the circumferential region are formed with a depth larger than or equal to that of the P-type column regions 106 in the element-forming region.

Abstract: A structure for use in a static induction transistor includes a semiconductor body having first and second semiconductor layers on a substrate, with the second layer having a dopant concentration of around an order of magnitude higher than the dopant concentration of the first layer. A plurality of sources are located on the second layer. A plurality of gates are ion implanted in the second layer, an end one of the gates being connected to all of the plurality of gates and constituting a gate bus. The gate bus has an extension connecting the gate bus in the second layer of higher dopant concentration to the first layer of lower dopant concentration. The extension is ion implanted in either a series of steps or a sloping surface which is formed in the first and second layers.