Abstract: A method for fabricating a field-effect-controllable semiconductor component includes providing a configuration having a semiconductor body with a front side, a rear side, a first terminal zone of a first conduction type, a channel zone of a second conduction type formed above the first terminal zone, and at least one control electrode adjacent the channel zone. The control electrode is insulated from the semiconductor body. A second terminal zone of the first conduction type is fabricated in the channel zone near the front side of the semiconductor body by: doping the channel zone near the front side with a first dopant concentration to fabricate a first zone of the first conduction type, and doping a section of the first zone with a second dopant concentration higher than the first dopant concentration to form a second zone of the first conduction type.

Abstract: A thyristor having a first zone, a second zone, a third zone, and a fourth zone. At least one control electrode is connected to the second and/or third zone. In order to reduce the static and dynamic power loss in a symmetrical thyristor, it is proposed that a field stop zone of the second conductivity type be disposed approximately in the center of the second zone, with the result that it subdivides the second zone into two sections of essentially the same size. To that end, the field stop layer is produced on an inner surface of a first wafer or of a second wafer, and the first wafer is connected to the second wafer, such that the two inner surfaces of the two wafers lie one on top of the other.

Abstract: A thyristor-based semiconductor device has a control port formed in a trench having a height-to-width aspect ratio that can be prohibitive to filling a bottom portion of the trench with an insulative material. According to an example embodiment of the present invention, a trench is formed in the substrate adjacent to a thyristor region, and a control port is formed near a bottom of the trench. An upper portion of the trench is then filled, thereby covering the control port. The control port is adapted to reduce the aspect ratio of a remaining portion of the trench over the control port, making it possible to fill trenches having a high height-to-width aspect ratio (e.g., at least 2:1). The thyristor control port is capacitively coupled to the thyristor region via a dielectric on a sidewall of the trench, and is configured and arranged to control current in the thyristor body via the capacitive coupling.

Abstract: A process for forming a trench gate power MOS transistor includes forming an epitaxial layer having a first type of conductivity on a semiconductor substrate, and forming a body region having a second type of conductivity on the epitaxial layer. A gate trench is formed in the body region and in the epitaxial layer. The process further includes countersinking upper portions of the gate trench, and forming a gate dielectric layer on surfaces of the gate trench including the upper portions thereof. A gate conducting layer is formed on surfaces of the gate dielectric layer for defining a gate electrode. The gate conducting layer has a thickness that is insufficient for completely filling the gate trench so that a residual cavity remains therein. The residual cavity is filled with a filler layer. The gate conducting layer is removed from an upper surface of the body region while using the filler layer as a self-aligned mask. The edge surfaces of the gate conducting layer are oxidized.

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

Abstract: A method for manufacturing an integrated circuit structure includes providing a semiconductor substrate and forming a thyristor thereon. The thyristor has at least four layers, with three P-N junctions therebetween. At least two of the layers are formed horizontally and at least two of the layers are formed vertically. A gate is formed adjacent at least one of the vertically formed layers. An access transistor is formed on the semiconductor substrate, and an interconnect is formed between the thyristor and the access transistor.

Abstract: The vertical insulated gate transistor includes, on a semiconductor substrate, a vertical pillar incorporating one of the source and drain regions at the top, a gate dielectric layer situated on the flanks of the pillar and on the top surface of the substrate, and a semiconductor gate resting on the gate dielectric layer. The other of the source and drain regions is in the bottom part of the pillar PIL and the insulated gate includes an isolated external portion 15 resting on the flanks of the pillar and an isolated internal portion 14 situated inside the pillar between the source and drain regions. The isolated internal portion is separated laterally from the isolated external portion by two connecting semiconductor regions PL1, PL2 extending between the source and drain regions, and forming two very fine pillars.

Abstract: A semiconductor device of the present invention has a pn-repeating structure that a structure in which a p-type impurity region (4) and an n-type drift region (3) are aligned side by side is repeated twice or more, and a low concentration region which is either p-type impurity region (4) or n-type drift region (3) located at the outermost portion of this pn-repeating structure has the lowest impurity concentration or has the least generally effective charge amount among all the p-type impurity regions (4) and n-type drift regions (3) forming the pn-repeating structure.

Abstract: A semiconductor device includes a thyristor body having at least one region in a substrate. According to an example embodiment of the present invention, a trench is in a substrate and adjacent to a thyristor body region in the substrate. The trench is lined with an insulative material and further includes conductive material that is insulated from the thyristor body region in the substrate by the liner material. A conductive thyristor control port is located in the trench and adapted for capacitively coupling to the thyristor body region in the substrate and to control current in the thyristor body by causing an outflow of minority carriers in the thyristor. With this approach, conductive material can be used to fill a portion of the trench while using the trench portion including the conductive material to electrically isolate a portion of the thyristor body in the substrate.

Abstract: A process for a trench power MOSFET comprises forming a trench on a semiconductor substrate and an oxide and nitride in the trench, etching the oxide and nitride to remain a part of them at the bottom of the trench, and subsequent procedure for the other structure of the trench power MOSFET. Due to the thick insulator formed at the bottom of the trench, the trench power MOSFET is improved by increased voltage endurance and reduced parasitic capacitance, and thereby the cell density is increased.

Abstract: This invention clarifies the effects of parameters and enables the mass production of a super-junction semiconductor device, which has a drift layer composed of a parallel pn layer that conducts electricity in the ON state and is depleted in the OFF state. The quantity of impurities in n drift regions is within the range between 100% and 150% or between 110% and 150% of the quantity of impurities in p partition regions. The impurity density of either one of the n drift regions and the p partition regions is within the range between 92% and 108% of the impurity density of the other regions. In addition, the width of either one of the n drift regions and the p partition regions is within the range between 94% and 106% of the width of the other regions.

Abstract: High density static memory cells and arrays containing gated lateral bipolar transistors which can be latched in a bistable on state. Each transistor memory cell includes two gates which are pulse biased during the write operation to latch the cell. Also provided is a CMOS fabrication process to create the cells and arrays.

Abstract: A method of fabricating trench power MOSFET is described. A first etching step is performed on a substrate to form a plurality of trenches and the substrate has a first doped region and a second doped region and serves as a drain region. A gate oxide layer and a polysilicon layer are then sequentially formed on the second doped region to create a gate region. Subsequent performance of a second etching step utilizes a mask layer to overlap the polysilicon layer. A portion of the second doped region is exposed and the exposed portion defines a base region. The polysilicon layer is etched to expose the gate oxide layer and the base region is simultaneously etched to remove a portion of the second doped region to expose the first doped region for forming an aligned source region. A contact region in the source region is finally formed to fabricate the trench power MOSFET.

Abstract: A semiconductor device includes a thyristor designed to reduce or eliminate manufacturing and operational difficulties commonly experienced in the formation and operation of NDR devices. According to one example embodiment of the present invention, the semiconductor substrate is trenched adjacent a doped or dopable substrate region, which is formed to included at least two vertically-adjacent thyristor regions of different polarity. A capacitively-coupled control port for the thyristor is coupled to at least one of the thyristor regions. The trench also includes a dielectric material for electrically insulating the vertically-adjacent thyristor regions. The thyristor is electrically connected to other circuitry in the device, such as a transistor, and used to form a device, such as a memory cell.

Abstract: A power semiconductor switching device such as a power MOSFET that includes breakdown voltage enhancement regions formed by self-alignment.

Abstract: A semiconductor device is provided which can be manufactured even by using an inexpensive FZ wafer in a wafer process and still has a sharp inclination of a high impurity concentration in a high impurity concentration layer at the outermost portion of the reverse side and at the boundary between the high impurity concentration and a low impurity concentration drift layer, thus achieving both low cost and a high performance. A method for manufacturing a semiconductor device is also provided which can form a high impurity concentration buffer layer and a high impurity concentration layer at the outermost portion of the reverse side without any significant trouble, even after the formation of an active region and an electrode thereof at the right side, to thereby achieve both low cost and high performance.

Abstract: In a method of manufacturing a semiconductor element (6) having a cathode (3) and an anode (5), the starting material used is a relatively thick wafer (1) to which, as a first step, a barrier region (21) is added on the anode side. It is then treated on the cathode side, and the thickness of the wafer (1) is then reduced on the side opposite to the cathode (3), and an anode (5) is produced on this side in a further step. The result is a relatively thin semiconductor element which can be produced economically and without epitaxial layers.

Abstract: A semiconductor device is provided which can be manufactured even by using an inexpensive FZ wafer in a wafer process and still has a sharp inclination of a high impurity concentration in a high impurity concentration layer at the outermost portion of the reverse side and at the boundary between the high impurity concentration and a low impurity concentration drift layer, thus achieving both low cost and a high performance. A method for manufacturing a semiconductor device is also provided which can form a high impurity concentration buffer layer and a high impurity concentration layer at the outermost portion of the reverse side without any significant trouble, even after the formation of an active region and an electrode thereof at the right side, to thereby achieve both low cost and high performance.

Abstract: A structure and a process for fabricating a bipolar junction transistor (BJT) that is compatible with the fabrication of a vertical MOSFET is disclosed. In the process, at least three layers of material are formed sequentially on a semiconductor substrate, where the substrate includes a buried collector region for the BJT and a source region for the MOSFET. After the at least three layers are formed on the substrate, two windows or trenches are formed in the layers. The first window terminates at the surface of the silicon substrate where the source region has been formed; the second window terminates at the buried collector region. Both windows are then filled with semiconductor material. For the BJT, the bottom portion of the window is filled with material of a conductivity type matching the conductivity of the buried collector, while the upper region of the semiconductor material is doped the opposite conductivity to form the BJT base.

Abstract: A process to make a low voltage (under 200 volts) superjunction device employs spaced P type implants into the generally central depth region of an epitaxially formed N layer. The wafer is then placed in a diffusion furnace and the spaced implants are driven upward and downward by 4 to 8 microns to form spaced P pylons in an N type epitaxial body. MOSgated structures are then formed atop each of the P pedestals. The total P charge of each pedestal is at least partially matched to the total N charge of the surrounding epitaxial material. The initial implant may be sandwiched between two discrete epitaxial layers.

Abstract: Semiconductor substrates suitable for making thin vertical current conducting devices are made by providing a relatively thick semiconducting substrate with at least one conductivity type having a thickness of from about 100 &mgr;m to 700 &mgr;m. At least one active device region is optionally first formed on a first side. Then the semiconducting substrate is thinned in at least one selected region on the other side below at least partially where the active device will be on the first side so as to have the selected region thinned to a thickness ranging from about 10 &mgr;m to 400 &mgr;m to form at least one deep trench.

Abstract: A thyristor includes a semiconductor body having an anode-side base zone of a first conductance type, and having a cathode-side base zone of the second, opposite conductance type, and has cathode-side and anode-side emitter zones. An anode-side defect zone is included within the anode-side base zone, in which the free charge carriers have a reduced life, with a predetermined thickness of at least 20 &mgr;m. The defect zone may be produced by anode-side irradiation of predetermined regions of the semiconductor body with charged particles, and with heat treatment of the semiconductor body in order to stabilize the defect zone.

Abstract: The present invention provides a method of forming a vertical replacement gate (VRG) device on a semiconductor substrate. The method includes depositing an epitaxial layer over a first source/drain region, implanting a layer within the epitaxial layer wherein the thickness of the layer substantially defines a channel length of the device and replacing the layer with a gate layer.

Abstract: A semiconductor device comprises a first semiconductor layer of a first conductivity type provided on a semiconductor substrate of the first conductivity type, a base layer of a second conductivity type provided in the first semiconductor layer, for defining a vertical MISFET including source regions and a gate electrode on a gate insulation film, a Schottky barrier diode (SBD)-forming region provided in the first semiconductor layer around the base layer, a guard ring region of the second conductivity type provided around SBD-forming region, a first main electrode disposed above the first semiconductor layer and provided in common as both a source electrode of the MISFET and an anode of the SBD, a surface gate electrode disposed above the first semiconductor layer, and a second main electrode provided in common as a drain electrode of the MISFET and a cathode of the SBD.

Abstract: In a semiconductor device, a p-type base region is provided in an n−-type substrate to extend from a principal surface of the substrate in a perpendicular direction to the principal surface. An n+-type source region extends in the p-type base region from the principal surface in the perpendicular direction, and an n+-type drain region extends in the substrate separately from the p-type base region with a drift region interposed therebetween. A trench is formed to penetrate the p-type base region from the n+-type source region in a direction parallel to the principal surface. A gate electrode is formed in the trench through a gate insulating film. Accordingly, a channel region can be formed with a channel width in a depth direction of the trench when a voltage is applied to the gate electrode.

Abstract: A capacitor for sensing a substrate voltage in an integrated circuit power device may be implemented by isolating a portion or segment of the metal layer that normally covers the heavily doped perimeter region typically used for electric field equalization. In conjunction, one or more portions of an isolation dielectric layer of silicon oxide are not removed from the surface of the semiconductor substrate, as is commonly done before depositing the metal layer. The portions of isolated silicon oxide which are not removed become the dielectric layer of the capacitor. Moreover, one plate of the capacitor is formed by the heavily doped perimeter region that is electrically connected to the substrate (e.g. a drain or collector region). The other plate is formed by the segment of metal isolated from the remaining metal layer defined directly over the heavily doped perimeter region.

Abstract: A high voltage semiconductor device and a method of forming the same is provided.

Abstract: A semiconductor device has an alternating conductivity type layer that improves the tradeoff relation between the ON-resistance and the breakdown voltage and a method of manufacturing such a semiconductor device. The alternating conductivity type layer is formed of n-type drift regions and p-type partition regions alternately arranged with each other. At least the n-type drift regions or p-type partition regions are formed by ion implantation under an acceleration voltage changed continuously. The p-type partition regions or n-type drift regions are formed by epitaxial growth or by diffusing impurities from the surface of a substrate or a layer for the layer.

Abstract: A semiconductor device comprises: a semiconductor layer of a first conductivity type; a pair of base regions of a second conductivity type selectively provided on a surface of the semiconductor layer; and source regions of a first conductivity type, each of the source regions being selectively provided on a surface of each of the base regions. The semiconductor device further comprises an electrical field reducing region of a second conductivity type selectively provided on the surface of the semiconductor layer between the pair of the base regions; a gate insulating film provided on the surface of the base regions; a pair of gate electrodes provided on the gate insulating film, each of the gate electrodes being provided on the surface of the base regions between the source region and the electrical field reducing region; and a source electrode connected to the source regions. The electrical field reducing region is isolated from both of the gate electrode and the source electrode.

Abstract: Vertical field effect transistors are fabricated by depositing a vertical channel on a microelectronic substrate at a thickness along the microelectronic substrate that is independent of lithography, the vertical channel extending orthogonal to the microelectronic substrate. Source and drain regions are formed at respective opposite ends of the vertical channel, and an insulated gate is formed adjacent the vertical channel. More specifically, a first doping layer is formed on a microelectronic substrate, an intermediate layer is formed on the first doping layer opposite the substrate and a second doping layer is formed on the intermediate layer opposite the first doping layer. A trench is then formed in the first doping layer, the intermediate layer and the second doping layer, the trench including a trench sidewall. The trench sidewall is lined with a conformal amorphous silicon layer.

Abstract: A power MOSFET is provided that includes a substrate of a first conductivity type. An epitaxial layer also of the first conductivity type is deposited on the substrate. First and second body regions are located in the epitaxial layer and define a drift region between them. The body regions have a second conductivity type. First and second source regions of the first conductivity type are respectively located in the first and second body regions. A plurality of trenches are located below the body regions in the drift region of the epitaxial layer. The trenches, which extend toward the substrate from the first and second body regions, are filled with a thin oxide layer and a polycrystalline semiconductor material (e.g., polysilicon) that includes a dopant of the second conductivity type.

Abstract: A method is provided for forming a power semiconductor device. The method begins by providing a substrate of a first or second conductivity type and then forming a voltage sustaining region on the substrate. The voltage sustaining region is formed by depositing an epitaxial layer of a first conductivity type on the substrate and forming at least one trench in the epitaxial layer. A barrier material is deposited along the walls of the trench. A dopant of a second conductivity type is implanted through the barrier material into a portion of the epitaxial layer adjacent to and beneath the bottom of the trench. The dopant is diffused to form a first doped layer in the epitaxial layer and the barrier material is removed from at least the bottom of the trench. The trench is etched through the first doped layer. A second doped layer is formed in the same manner as the first doped layer. The second doped layer is located vertically below the first doped layer.

Abstract: Doping of the P type base region in a MOSFET or an IGBT with a combination of boron and one or more of indium, aluminum and gallium, provides a structure having a lower P type doping level in the channel portion of the structure than in the remainder of the structure without requiring counter doping of the channel. The doping level of the emitter region of an MCT is kept high everywhere except in the channel in order to provide a fast turn-off time for the MCT.

Abstract: J-FET having a first semiconductor region (2, 3), which comprises a first contact (7) with a highly doped contact layer (8) serving as a source disposed between two second contacts (9) serving as a gate on its first surface (4). The three contacts (7, 9) are each connected to a respective second semiconductor region (5, 6). The first and second semiconductor regions (2, 3, 5, 6) are of opposite conductivity types. The second semiconductor regions (5) connected to the second contacts (9) extend in the first semiconductor region (2, 3) below the second semiconductor region (6) that is connected to the first contact (7), with the result that the three second semiconductor regions (5, 6) at least partially overlap in a projection onto a horizontal plane and a channel region (11) is formed between the three second semiconductor regions (5, 6) in the first semiconductor region (2, 3).

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

Abstract: Formed in a part of the base region is an impurity diffusion region extending in a vertical direction and having an impurity concentration lower than that in the other portion of the base region. By the formation of the impurity diffusion region, the depletion layer is extended toward the base region so as to improve the breakdown voltage. The impurity diffusion region is formed by forming a trench in a part of the base region, a conductive film being buried in the trench, followed by introducing by ion implantation an impurity of the conductivity type equal to that in the base region into the side wall and the bottom of the trench in a concentration lower than that in the base region and subsequently diffusing the implanted impurity ions. The impurity diffusion region thus formed permits relaxing the electric field concentration on the corner portion of the gate trench and on the extended portion of the base region so as to improve the breakdown voltage.

Abstract: A negative buffer layer and a positive collector layer are formed on a side of one surface of a semiconductor substrate. The positive collector layer is set to have a low dose amount and set shallow so that a low injection efficiency emitter structure is realized. Break down voltage of a power device is controlled by a thickness of a drift layer. A positive base layer, a negative emitter layer and a positive base contact layer are formed on a side of the other surface of the semiconductor substrate. A negative low resistant layer reduces a junction FET effect. An emitter electrode comes into contact with the negative emitter layer and the positive base contact layer. A collector electrode comes into contact with the positive collector layer. A gate electrode is formed on a gate insulating film above a channel region on a surface portion of the positive base layer.

Abstract: A semiconductor device is provided which can be manufactured even by using an inexpensive FZ wafer in a wafer process and still has a sharp inclination of a high impurity concentration in a high impurity concentration layer at the outermost portion of the reverse side and at the boundary between the high impurity concentration and a low impurity concentration drift layer, thus achieving both low cost and a high performance. A method for manufacturing a semiconductor device is also provided which can form a high impurity concentration buffer layer and a high impurity concentration layer at the outermost portion of the reverse side without any significant trouble, even after the formation of an active region and an electrode thereof at the right side, to thereby achieve both low cost and high performance.

Abstract: A semiconductor device includes an improved drain drift layer structure of alternating conductivity types, that is easy to manufacture, and that facilitates realizing a high current capacity and a high breakdown voltage and to provide a method of manufacturing the semiconductor device. The vertical MOSFET according to the invention includes an alternating-conductivity-type drain drift layer on an n+-type drain layer as a substrate. The alternating-conductivity-type drain drift layer is formed of n-type drift current path regions and p-type partition regions alternately arranged laterally with each other. The n-type drift current path regions and p-type partition regions extend in perpendicular to n+-type drain layer. Each p-type partition region is formed by vertically connecting p-type buried diffusion unit regions Up. The n-type drift current path regions are residual regions, left after connecting p-type buried diffusion unit regions Up, with the conductivity type thereof unchanged.

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

Abstract: A method is provided for forming a power semiconductor device. The method begins by providing a substrate of a first or second conductivity type and then forming a voltage sustaining region on the substrate. The voltage sustaining region is formed by depositing an epitaxial layer of a first conductivity type on the substrate and forming at least one trench in the epitaxial layer. A first layer of polysilicon having a second dopant of the second conductivity type is deposited in the trench. The second dopant is diffused to form a doped epitaxial region adjacent to the trench and in the epitaxial layer. A second layer of polysilicon having a first dopant of the first conductivity type is subsequently deposited in the trench. The first and second dopants respectively located in the second and first layers of polysilicon are interdiffused to achieve electrical compensation in the first and second layers of polysilicon.

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

Abstract: A method for manufacturing a semiconductor device constituting an JGHT is provided that allows to manufacture the device using an inexpensive wafer and with high yields, and achieves low losses. Specifically, after an emitter electrode is formed, a reverse principal surface is polished to a specified thickness. The center line average height Ra of the polished surface is controlled to be not more than 1 &mgr;m, and the filtered center line waviness Wca is kept within 10 &mgr;m. The polished surface is selectively cleaned with an aqueous chemical solution to remove particles. To the cleaned surface, phosphorus ions arc implanted for forming a field-stop layer and boron ions are implanted for forming a collector layer. The wafer is then put into a diffusion furnace and annealed at a temperature from 300° C. to 550° C. to form a field-stop layer and a collector layer. Finally, a collector electrode is formed.

Abstract: A method for improving gate oxide thinning issue at trench corners is disclosed. The method comprises steps as follows. Firstly, a silicon substrate having a trench therein is provided. HDPCVD technology to form a first oxide layer on the sidewall and the bottom of the trench is carried out. After performing an etchback to leave the first oxide layer on the bottom of the trench, a second oxide layer is formed on the first oxide layer and on sidewalls of the trench by LPCVD technology. Thereafter, an isotropic etching is performed so as to remove a substantially portion of the second oxide layer and leave a remnant portion of second oxide layer on the trench corners. As a consequently, the trench corners are smooth. Finally, a thermal oxidation to form a third oxide layer on the sidewall of the trench is carried achieved to accomplish the gate oxide formation.

Abstract: Openings are formed in a laminate of a polycrystalline silicon film and an LTO film on a channel layer. While the laminate is used as a mask, impurities are implanted into a place in the channel layer which is assigned to a source region. Also, impurities are implanted into another place in the channel layer which is assigned to a portion of a second gate region. A portion of the polycrystalline silicon film which extends from the related opening is thermally oxidated. The LTO film and the oxidated portion of the polycrystalline silicon film are removed. While a remaining portion of the polycrystalline silicon film is used as a mask, impurities are implanted into a place in the channel layer which is assigned to the second gate region. Accordingly, the source region and the second gate region are formed on a self-alignment basis which suppresses a variation in channel length.

Abstract: A RESURF trench gate MOSFET has a sufficiently small pitch (close spacing of neighbouring trenches) that intermediate areas of the drain drift region are depleted in the blocking condition of the MOSFET. However, premature breakdown can still occur in this known device structure at the perimeter/edge of the active device area and/or adjacent the gate bondpad.

Abstract: An N+ buffer layer formed on the underside of an N− layer includes an inactive region having incompletely activated ions and an active region having highly activated ions. The carrier concentration of the active region is higher than that of the inactive region. In the inactive region, the electrical activation rate X of the ions is expressed as 1%≦X≦30%. It is thus possible to achieve a PT structure using a Raw wafer, which reduces manufacturing costs and suppresses power consumption.

Abstract: On an insulating substrate, there are formed a first gate electrode, a gate insulating film, a semiconductor film, and an interlayer insulating film. Above the interlayer insulating film, a TFT is formed having a second gate electrode connected to the first gate electrode. Then, a photosensitive resin is formed over the entire surface of the extant layers. Subsequently, first exposure is applied using a first mask, and second exposure is then applied using a second mask with a larger amount of light than used for the first exposure. The second mask has an opening at a position corresponding to a source. Thereafter, the photosensitive resin film is developed thereby forming a contact hole and a concave.

Abstract: In a semiconductor device having high voltage resistance and low ON voltage characteristics, charge-storage regions (insulation layer) are formed in a drift region. Formed above the drift region are a channel region, an emitter region, trench-type gate electrodes, and an emitter electrode. Strips of the insulation layer extend in a direction intersecting a direction of extension of the gate electrodes, and form a stripe pattern. The insulation layer curbs extraction of holes into the channel region. Openings in the stripe pattern of the insulation layer form depletion layers.

Abstract: In a trench-gate field-effect transistor of inverted configuration, the drain region (14) is adjacent to the surface with the insulated trench-gate structure (11,12). The gate dielectric 12 is thicker adjacent to the drain region (14), and preferably also the drain drift region (14a), than it is adjacent to the channel-accommodating portion (15a) of the transistor body region (15). Another portion (15b) of the transistor body region (15) is electrically shorted to the underlying source region (13) by a buried electrical short (35). This buried short is provided by a leaky p-n junction (35) between a highly doped (p+) bottom portion (15b) of the body region and the underlying source region (13), at an area that is separated laterally from the insulated gate electrode (11) by an active portion (13a) of the source region adjacent to the gate trench (20). This portion (13a) of the source region can be formed by dopant implantation and/or diffusion via the lower portion of the trench (20).