Abstract: A semiconductor device having both functional and non-functional or dummy lines, regions and/or patterns to create a topology that causes the subsequently formed spacers to be more predictable and uniform in shape and size.

Abstract: The invention is related to a method for fabricating a channel region of a transistor device by ion implantation with a large angle and the transistor device formed therefrom. The transistor device is formed on a substrate. Furthermore, the ion implantation with a large angle forms the channel of the transistor in order to prevent the punchthrough phenomenon between the source region and the drain region. In addition, the profile of the channel region is compact and non-uniform. Therefore the ion concentration is higher in the middle of the channel region than in the other regions. Thus, the parasitic capacitance and the junction leakage can be reduced. The carrier mobility is higher than that of the prior art. Moreover, the threshold voltage is more easily controlled than that of the prior art.

Abstract: A semiconductor device of the invention is formed so that the impurity concentration of a semiconductor substrate (1) under a source diffusion layer (2) is lower than the impurity concentration on a source side of a p-type impurity diffusion layer (6). Therefore, in the semiconductor device of the invention, the junction capacitance of the p-n junction between the source and the substrate is smaller as compared with a conventional LDC structure. In general, the speed of a device is proportional to the product obtained by multiplying together a load capacitance and an inverse of a current value of the device. Accordingly, in the case of applying the present invention to a circuit such as a NAND type CMOS circuit in which a voltage is applied to a region between the source and the substrate, the speed of the device is not decreased. On the other hand, the power consumption of a device is proportional to the product obtained by multiplying together a load capacitance and the square of an applied voltage.

Abstract: Methods of forming field effect transistors and related field effect transistor constructions are described. A masking layer is formed over a semiconductive substrate and an opening having sidewalls is formed therethrough. The opening defines a substrate area over which a field effect transistor gate is to be formed. A dopant of a first conductivity type is provided through the opening and into the substrate. Sidewall spacers are formed over respective sidewalls of the opening. Enhancement dopant of a second conductivity type which is different from the first conductivity type is provided through the opening and If into the substrate. A transistor gate is formed within the opening proximate the sidewall spacers, and source/drain regions of the second conductivity type are diffused into the substrate operably proximate the transistor gate. The first conductivity type dopant forms a halo region proximate the source/drain regions and lightly doped drain (LDD) regions for the transistor.

Abstract: In a field effect transistor, an element isolation trench is formed around the element region on the major surface of a silicon substrate. A gate electrode is formed on the major surface in the element region via a gate insulating film. Source and drain regions are formed on the major surface of the element region to oppose via a channel region under the gate electrode. The channel region has a main portion having an upper surface at a level higher than the upper end portion of a trench side wall, and a side portion having an upper surface tilting downward from the main portion to the upper end portion of the trench side wall. The dopant impurity in the channel region has a concentration peak located at a level lower than the upper end portion of the trench side wall. The distance from the upper surface of the main portion to the concentration peak is larger than that from the upper surface of the side portion to the peak.

Abstract: A semiconductor device is fabricated by injecting fluorine into a region of a semiconductor substrate other than a region of the semiconductor substrate where a thinnest gate insulating film is to be formed, among a plurality of regions where gate insulating films are to be formed. Then, the semiconductor substrate with fluorine injected therein is oxidized to form an oxide film in the plurality of regions. A surface of the oxide film is nitrided to turn a surface layer thereof into an oxynitride film or form a nitride film on the surface of the oxide film. The semiconductor device has a plurality of gate insulating films of different thicknesses which contain nitrogen in their surface layers.

Abstract: A lateral high-voltage transistor has a semiconductor body made of a lightly doped semiconductor substrate of a first conductivity type and an epitaxial layer of a second conductivity type. The epitaxial layer is provided on the semiconductor substrate. The lateral high-voltage transistor has a drain electrode, a source electrode, a gate electrode and a semiconductor zone of the first conductivity type which is provided under the gate electrode and is embedded in the epitaxial layer. Between the source electrode and the drain electrode trenches are provided in lines and rows in the semiconductor layer. The walls of the trenches are highly doped with dopants of the first conductivity type.

Abstract: A semiconductor device and a method for fabricating the same are disclosed that reduce short channel effects to improve device characteristics. The semiconductor device includes a gate insulating film formed on a semiconductor substrate, a gate electrode formed on the gate insulating film and a lightly doped region formed in the semiconductor substrate at both sides of the gate electrode. A sidewall insulating film is formed at both sides of the gate electrode and a heavily doped impurity region is formed in the semiconductor substrate extending from the sidewall insulating film. Further, an insulating film is formed at sides of the heavily doped impurity region. The insulating film prevents impurity ions from the heavily doped impurity region from diffusing into the channel region of the device.

Abstract: A method for forming a semiconductor device with a doped channel-region, and the device formed therefrom. In one embodiment, the method invention is comprised of two principal steps. The first step is to provide a semiconductor substrate to which the following process steps can be performed. The second step is to create a doping profile into the channel-region of the semiconductor substrate. The doping profile is created by a) performing a first doping implantation with a first dopant in a first concentration to a first depth within the semiconductor substrate, and b) performing a second doping implantation with a second dopant in a second concentration to a second depth within the semiconductor substrate.

Abstract: A method for manufacturing a CMOS sensor comprises the steps of providing a substrate having a first conductive type, wherein the substrate comprises an isolation region, an active region, a gate structure on the active region and a source/drain region having a second conductive type in the substrate. A patterned photoresist is formed over the substrate. A first doped region having the second conductive type is formed across a portion of the source/drain region and extends from the surface of the substrate into the substrate. A second doped region having the first conductive type is formed to wrap the first doped region in the substrate. A third doped region having the second conductive type is formed under the second doped region. A fourth doped region having the first conductive type is formed under the third doped region. The patterned photoresist is removed.

Abstract: A transistor fabrication process is provided which derives a benefit from having barrier atoms incorporated in a lateral area under a gate oxide of the transistor in close proximity to the drain. To form the transistor, a gate oxide layer is first grown across a silicon-based substrate. A polysilicon layer is then deposited across the gate oxide layer. Portions of the polysilicon layer and the oxide layer are removed to form a gate conductor and gate oxide, thereby exposing source-side and drain-side junctions within the substrate. An LDD implant is performed to lightly dope the source-side and drain-side junctions. An etch stop material may be formed upon opposed sidewall surfaces of the gate conductor, the upper surface of the gate conductor, and the source-side and drain-side junctions. Spacers may then be formed laterally adjacent the etch stop material located upon sidewall surfaces of the gate conductor.

Abstract: A floating-gate memory which uses a skewed reference for sensing. The skewed reference preferably has a substantially different VT implant dose than the array cells, and can also have different sizing.

Abstract: In important applications of circuits comprising transistors of the lateral DMOST type, such as (half) bridges, the voltage on the output may become higher or lower than the supply voltage or earth in the case of an inductive load. The injection of charge carriers into the substrate can be prevented by screening the drain (18) of the Low-Side transistor from the substrate by means of a p-type buried layer (13) and an n-type buried layer (14) below said p-type buried layer. In order to avoid parasitic npn-action between the n-type buried layer (14) and the n-type drain (18), not only the back-gate regions (16a, 16c) at the edge of the transistor, but also the back-gate regions (16b) in the center of the transistor, are connected to the p-type buried layer, for example by means of a p-type well. As a result, throughout the relatively high-ohmic buried layer, the potential is well defined, so that said npn-action is prevented.

Abstract: A lateral PNP transistor (LPNP) (102) having the low resistance base buried N+ region (114) removed from below the emitter region (118). This leaves a high resistance n-well (116) below the emitter. The resistance from the center of the emitter region (118) to the N+ buried region (114) is greater than the resistance at the periphery of the emitter region (118) to the N+ buried region (114). Debiasing will occur in the center of the emitter region (118) where the parasitic base current is generated. Thus, the ratio of parasitic current to active collector current and peak beta will improve.

Abstract: The invention relates to a high-voltage deep depletion transistor, provided in a semiconductor body (1) having a substrate (2) of a first conductivity type, for example the p-type, and a surface layer (3) of the opposite conductivity type, for example the n-type for an n-channel transistor. To prevent formation of inversion layers below the gate, the channel is subdivided into a plurality of sub-channel regions (7a, 7b, 7c, 7d) mutually separated by p-type regions (11a, 11b, 11c, 11d) which serve to remove generated holes. The p-type regions extend across the whole thickness of the channel and are contacted via the substrate. Each sub-channel region may be subdivided further by intermediate p-type regions (13) to improve the removal of holes.

Abstract: The invention relates to a SOI deep depletion MOS transistor provided in a thin silicon layer (5) adjoining a surface (4) of a silicon body (3) and insulated from a silicon substrate (7) by a buried oxide layer (6). The channel region (13) of a first conductivity type is provided with at least one and preferably a plurality of zones (16) of the opposite conductivity type adjoining the surface to remove minority carriers from the interface between the channel and the gate oxide (15). The zones (16) extend across the whole thickness of the channel and adjoin the buried oxide at the side of the channel remote from the gate dielectric. Due to this construction, minority carriers are removed also from the rear side of the channel. This enables the transistor to be operative also at high voltages having values at which the substrate and the buried oxide operate as a second gate and as a second gate dielectric, respectively.

Abstract: In a field effect transistor, an element isolation trench is formed around the element region on the major surface of a silicon substrate. A gate electrode is formed on the major surface in the element region via a gate insulating film. Source and drain regions are formed on the major surface of the element region to oppose via a channel region under the gate electrode. The channel region has a main portion having an upper surface at a level higher than the upper end portion of a trench side wall, and a side portion having an upper surface tilting downward from the main portion to the upper end portion of the trench side wall. The dopant impurity in the channel region has a concentration peak located at a level lower than the upper end portion of the trench side wall. The distance from the upper surface of the main portion to the concentration peak is larger than that from the upper surface of the side portion to the peak.

Abstract: The present invention is a semiconductor device having and a method for forming wells by growing an epitaxial silicon layer wherein the epitaxial silicon layer has at least three silicon sublayers. The first sublayer is highly doped, the second sublayer is less doped, and the third sublayer is also highly doped. The use of the epitaxially grown wells allows for the placement of high dopant concentrations in regions of the well where electrical isolation is an issue and the placement of lower doped concentrations in regions of the well where electrical isolation is not as great an issue in order to help reduce the problem of parasitic capacitance.

Abstract: A lateral MOSFET (100) and a method for making the same. A two layer raised source/drain region (106) is located adjacent a gate structure (112). The first layer (106a) of the raised source drain is initially doped p-type and the second layer (106b) of the raised source/drain region is doped n-type. P-type dopants from first layer (106a) are diffused into the substrate to form a pocket barrier region (105). N-type dopants from second layer (106b) diffuse into first layer (106a) so that it becomes n-type and into the substrate to form source/drain junction regions (104). P-type pocket barrier region (105) thus provides a barrier between the source/drain junction regions (104) and the channel region (108).

Abstract: A MOSFET having a buried channel structure and an adjacent surface channel structure between a source region and a drain region. The surface channel structure is preferably formed adjacent the source region via angular implantation techniques. By combining the advantages of the surface channel device with the buried channel device, the resulting hybrid MOSFET structure has improved drive current and switching characteristics.

Abstract: A semiconductor memory device comprising a source and a drain formed in a P-type semiconductor substrate and a floating gate and a control gate constituting a two-layer gate. Electric-field moderating layer is provided in the P-type semiconductor substrate to contact with a side face of the drain. P-type region is formed in contact with channel region side surface and bottom surface of the electric-field moderating layer. P-type region lower part of the P-type region in contact with the bottom surface of the electric-field moderating layer is given a lower impurity concentration than P-type region side part formed at the channel region side of the electric-field moderating layer. By this means it is possible to increase the writing speed of the semiconductor memory device while suppressing delay in the switching speed during reading operation.

Abstract: A MOS gate and associated source/drain region structure providing three junction diodes between a source/drain contact area and the substrate, instead of the typical total of one, resulting in improved isolation of a source/drain contact area and a storage node which may be formed thereat. For fabricate the structure, a source/drain region is formed in a substrate having a space charge in the bulk or major part thereof, the source/drain region including: a first region having a space charge with a charge opposite that of a space charge in the major part of the substrate; a second region separated from the major part of the substrate by the first region and having a space charge with a charge opposite that of the space charge of the first region; and a third region separated from the first region and the major part of the substrate by the second region and having a space charge with a charge opposite that of the space charge of the second region.

Abstract: An ultra-large scale integrated circuit semiconductor device having a laterally non-uniform channel doping profile is manufactured by using a Group IV element implant at an implant angle of between 0° to 60° from the vertical to create interstitials in a doped silicon substrate under the gate of the semiconductor device. After creation of the interstitials, a channel doping implantation is performed using a Group III or Group V element which is also implanted at an implant angle of between 0° to 60° from the vertical. A rapid thermal anneal is then used to drive the dopant laterally into the channel of the semiconductor device by transient enhanced diffusion.

Abstract: A semiconductor structure with a heavily doped buried breakdown region and a method for manufacture. A source region is disposed in a substrate and is doped with dopant of a type opposite that of the substrate. A drain region is disposed in the substrate at the surface and doped with dopant which is the same as that of the source region, and a gate structure is disposed on the substrate between the source and drain regions. A breakdown region is disposed in the substrate below the drain region and is heavily doped with dopant of a type opposite that of the drain region in order to control the value and location of breakdown.

Abstract: A transistor is formed on the substrate (10) with a graded doping profile for the gate electrode (22). This graded profile is performed for an N-channel transistor by depositing the gate electrode with two separate layers of material. The first layer is a thin layer of N-doped poly, whereas the second layer is a layer of P-doped poly (18). A layer of cap oxide (20) is disposed over the gate electrode (22) to prevent further implantation of impurities during the source/drain implant operation.

Abstract: A logical circuit device has a MOS transistor having a source region, a drain region, a channel region defined between the source region and the drain region, and a gate electrode formed above the channel region, respectively formed on a semiconductor substrate. The amplitude of a voltage applied to the gate electrode necessary for making the channel region conductive is not level throughout the channel region in the width direction. Using such a logical circuit device, flip-flop circuits and storage circuits of a multivalued logic type can be realized.

Abstract: A high voltage metal oxide semiconductor device. The high voltage device comprises a high voltage NMOS, a high voltage PMOS, or a high voltage CMOS. A field oxide layer is used to isolate the gate from the source region, while a diffusion region is formed under the field oxide layer. A channel region around the source drain extends across a first doped well and a second doped well having different dopant concentration. The channel region further comprises two grading regions with different dopant concentrations around the drain region.

Abstract: Dot-pattern-like impurity regions are artificially and locally formed in a channel forming region. The impurity regions restrain the expansion of a drain side depletion layer toward the channel forming region to prevent the short channel effect. The impurity regions allow a channel width W to be substantially fined, and the resultant narrow channel effect releases the lowering of a threshold value voltage which is caused by the short channel effect.

Abstract: There are provided a double-diffused MOS (Metal Oxide Semiconductor) transistor and a fabricating method thereof. In the double-diffused MOS transistor, a buried layer of a first conductive type and an epitaxial layer of the first conductive type are sequentially formed on a semiconductor substrate, and a gate electrode is formed on the epitaxial layer of the first conductive type with interposition of a gate insulating film. Source and drain regions of the first conductive type are formed in the surface of the epitaxial layer of the first conductive type in self-alignment and non-self-alignment with the gate electrode, respectively. A body region of a second conductive type is formed in the surface of the epitaxial layer of the first conductive type to be surrounded by the source region of the first conductive type, and a bulk bias region of the second conductive type is formed in the body region of the second conductive type under the source region of the first conductive type.

Abstract: A method for fabricating an integrated circuit is presented. In the method, a substrate is provided having a dielectric base layer formed thereupon. Source/drain trenches may be formed in the dielectric base layer. Source/drain structures containing metal may then be formed within the source/drain trenches. The upper surface of the dielectric base layer is then recessed a recession depth below upper surfaces of the source/drain structures. A gate trench is thus defined between upper portions of the source/drain structures extending above the upper surface of the dielectric base layer. A conductive channel layer is subsequently formed at least partially within the gate trench. A gate conductive layer may then be formed above the conductive channel layer and at least partially within the gate trench.

Abstract: An improved MOS transistor and method for making it are described. The MOS transistor's source and drain have a first conductivity type and are separated from each other by a first region having a second conductivity type opposite to the first conductivity type. A second region, also having the second conductivity type, is formed adjacent to the drain and is separated from the first region by the drain.

Abstract: A boron diffusion region is formed at a surface of a silicon substrate. A pair of n-type source/drain regions are formed at a surface of boron diffusion region. A gate electrode is formed at a region located between paired source/drain regions with a gate insulating film therebetween. A nitrogen implanted region is formed at the surface of silicon substrate located between paired n-type source/drain regions. Nitrogen implanted region has a peak nitrogen concentration at a position of a depth not exceeding 500 .ANG. from the surface of silicon substrate. Thereby, a transistor structure which can be easily miniaturized can be obtained.

Abstract: A p-type high concentration doped region is formed in a p-type semiconductor substrate between a n-type doped region as part of an input protection circuit and another n-type doped region as part of internal circuitry. A plate is divided into two over the high concentration doped region. The high concentration doped region suppresses generation of a parasitic MOS transistor with the plate for a gate, one of the n-type doped regions for a source, and the other for a drain.

Abstract: The present invention is a semiconductor device comprising an isolated N-type diffusion layer formed on part of a P-type semiconductor substrate or P-type well, a P-type channel barrier region formed so as to contact at least one part of the N-type diffusion layer, and an electrode drawn from the N-type diffusion layer through a contact hole; and constituting check elements to check the state of the P-type channel barrier region through measuring the junction withstand voltage of the N-type diffusion layer. With the aforementioned constitution, the state of the P-type channel barrier region can be checked with good sensitivity and without true breakdown of the thin oxide film having the same thickness as the gate oxide and influence from variations in the thickness of the field oxide, because the state of the P-type channel barrier region is checked by measuring the junction withstand voltage of the N-type diffusion layers.

Abstract: An LDD-structured field-effect semiconductor device that can eliminate fluctuations in the threshold voltage caused by variations in the position of higher-density diffusion layers, thereby suppressing variations in the threshold voltage to a lower level. The junction depth of each of the lower-density diffusion layers in contact with a substrate is greater than the depth of a depletion layer at the place corresponding to a portion of the channel region contacting the source region. This prevents a change in the positional relationship between diffusion layers serving as, what are referred to as "pocket layers", and the depletion layer adjacent to the source, even though the position of the higher-density diffusion layers is varied in the longitudinal direction of the channel due to variations in the width of a spacer.

Abstract: A fabrication method for a MOSFET device including the steps of forming a first insulating film on a semiconductor substrate wherein an active region and an isolated region are defined, forming a channel ion region by implanting impurity ions into the active region of the semiconductor substrate, forming a first conductive film pattern on a portion of the semiconductor substrate which corresponds to the channel ion region, forming a channel region having lower concentration than the channel ion region by implanting impurity ions in a different type from the ions in the channel ion region into a center portion of the channel ion region through the first conductive film pattern, forming a second conductive film pattern on the first conductive film pattern, forming an impurity region of low concentration in the semiconductor substrate with the first and second conductive film patterns as a mask, forming a sidewall spacer at both sides of the first and second conductive film patterns, and forming an impurity regi

Abstract: A metal-oxide-semiconductor (MOS) device in which the nonuniform dopant concentration in the channel region is obtained by means of ion implantation through a polysilicon gate electrode of nonuniform cross section, which is itself obtained by oxidizing the polysilicon using a semirecessed LOCOS process.

Abstract: An insulated-gate field-effect transistor utilizes local threshold-adjust doping to control the voltage at which the transistor turns on. The local threshold-adjust doping is present along part, but not all, of the lateral extent of the channel. In the transistor structure, a channel zone laterally separates a pair of source/drain zones. The channel zone is formed with a main channel portion and a more heavily doped threshold channel portion that contains the local threshold-adjust doping. Gate dielectric material vertically separates the channel zone from an overlying gate electrode. The transistor is a long device in that the gate electrode is longer, preferably at least 50% longer, than the gate electrode of a minimum-sized transistor whose gate length is approximately the minimum feature size. The long-gate transistor is suitable for use in analog and high-voltage digital portions of a VLSI circuit.

Abstract: A fine semiconductor device having a short channel length while suppressing a short channel effect. Linearly patterned or dot-patterned impurity regions 104 are formed in a channel forming region 103 so as to be generally parallel with the channel direction. The impurity regions 104 are effective in suppressing the short channel effects. More specifically, the impurity regions 104 suppress expansion of a drain-side depletion layer, so that the punch-through phenomenon can be prevented. Further, the impurity regions cause a narrow channel effect, so that reduction in threshold voltage can be lessened.

Abstract: A method for making an asymmetric MOS device having a notched gate oxide is disclosed herein. Such MOS devices have a region of a gate oxide adjacent to either the source or drain that is thinner than the remainder of the gate oxide. The thin "notched" region of gate oxide lies over a region of the device's channel region that has been engineered to have a relatively "high" threshold voltage (near 0 volts) in comparison to the remainder of the channel region. This region of higher threshold voltage may be created by a pocket region of increased dopant concentration abutting the source or the drain (but not both) and proximate the channel region. The pocket region has the opposite conductivity type as the source and drain. A device so structured behaves like two pseudo-MOS devices in series: a "source FET" and a "drain FET." If the pocket region is located under the source, the source FET will have a higher threshold voltage and a much shorter effective channel length than the drain FET.

Abstract: A triple well structure for an embedded dynamic random access memory uses an ion implantation performed on a portion of the first conductive type substrate between a second conductive type source and a second conductive type deep well. A first conductive type block region is formed between the second conductive type source and the second conductive type deep well.

Abstract: Impurity regions shaped in linear patterns are formed in parallel with the channel direction (electric field direction) in a channel forming region. The impurity regions restrain the expansion of the drain side depletion layer, and the narrow channel effect is exhibited to prevent the short channel effect. Also, in the channel forming region, the impurity regions control the carrier moving directing in one way, to thereby restrain the scattering caused by irregular collision between the carriers.

Abstract: A semiconductor device has a semiconductor substrate of a first conductivity type. A first well of a second conductivity type is disposed in the semiconductor substrate. A second well of the first conductivity type is disposed in the first well. A third well of the second conductivity is disposed in the second well. A MOS transistor having a source region and a drain region of the first conductivity type is disposed in the third well.

Abstract: An improvement of a resistance to electrostatic discharge of a semiconductor integrated circuit device is aimed. An IC having a high ESD immunity is realized by causing a surface concentration of N type impurities in a drain area of an N-channel type MOS transistor to be more than 5 E 18/cm.sup.3 in maximum in the direction of gate electrode of a gate electrode terminal and to have a monotonous concentration profile in which there is no kink in a portion less than 5 E 18/cm.sup.3 in the surface direction.

Abstract: An MOS transistor with high voltage sustaining capability and low closing resistance comprises a substrate (10) provided with a doping of a first conductive type, and a well area (20) formed in the substrate (10) and provided with a doping of a second conductive type opposite to the first conductive type. Further, the MOS transistor comprises source and drain areas (26,28) of the first conductive type formed in the well area (20). The MOS transistor is provided with a gate (32) comprising a gate oxide layer (36) and arranged between the source region (26) and the drain area (28), the gate (32) having drain-side end region (42) arranged at a distance (40) from the drain area (28). The MOS transistor comprises a drain extension region (24) provided with a doping of the first conductive type and having the drain area (28) arranged therein, with the drain extension region (24) reaching below the drain-side end region (42) of the gate (32).

Abstract: A graded-channel semiconductor device (10) is formed in a pedestal (12). The pedestal (12) is formed on a substrate (11) and improves the electrical characteristics of the device (10) compared to conventional device structures. The pedestal (12) has sides (13) that are bordered by a dielectric layer (24) to provide electrical isolation. The semiconductor device (10) includes a drain extension region (101) that extend from a drain region (44) to a gate structure (20). The semiconductor device (10) also has a conductive structure (105) that is adjacent to the gate structure (20).

Abstract: A novel high-speed, highly reliable VLSI manufacturable metal oxide semiconductor transistor with self-aligned punchthrough stops. A gate insulating layer is formed on a substrate having a first concentration of a first conductivity type. An inner gate electrode of a predetermined length and width is formed on the gate insulating layer. The inner gate electrode has laterally opposite sidewalls along the width of the inner gate electrode. A first and second punchthrough stop regions of a second concentration of the first conductivity type wherein the second concentration is greater than the first concentration, are disposed in the substrate in alignment with the laterally opposite sidewalls of the inner gate electrode. A pair of conductive spacers adjacent to and in electrical contact with respective laterally opposite sidewalls of the inner gate electrode are formed on the gate insulating layer of the transistor. The conductive spacers, along with the inner gate electrode, form a MOSFET gate electrode.

Abstract: A gate insulating film and gate electrodes are formed on a substrate containing N-type impurities such as P or As. Under the gate insulating film is a gate region on both sides of which are a first and a second source drain region. The gate region is furnished in its central part with a high-concentration channel injection region containing N-type impurities at a concentration higher than that of the substrate. Between the high-concentration channel injection region on the one hand and the first and the second source drain region and on the other hand, there are formed a first and a second low-concentration channel injection region and having substantially the same impurity concentration as that of the substrate.

Abstract: A CMOS logic gate for a semiconductor apparatus having a buried channel NMOS transistor and a fabrication method of the same are disclosed. The CMOS logic gate according to the present invention includes a pull up unit gate-connected by an input voltage and pulling up an output voltage, a buried channel NMOS transistor connected with the pull up unit and gate-connected by a power voltage, and a surface channel NMOS transistor connected with the buried channel NMOS transistor and gate-connected by the input voltage for pulling down the output voltage for thereby enhancing a reliability of the CMOS logic gate.

Abstract: An asymmetric insulated-gate field-effect transistor is configured in an asymmetric lightly doped drain structure that alleviates hot-carrier effects and enables the source characteristics to be decoupled from the drain characteristics. The transistor has a multi-part channel formed with an output portion, which adjoins the drain zone, and a more heavily doped input portion, which adjoins the source zone. The drain zone contains a main portion and more lightly doped extension that meets the output channel portion. The drain extension extends at least as far below the upper semiconductor surface as the main drain portion so as to help reduce hot-carrier effects. The input channel portion is situated in a threshold body zone whose doping determines the threshold voltage. Importantly, the provision of a lightly doped source extension is avoided so that improving the drain characteristics does not harm the source characteristics, and vice versa.