Abstract: A commutator utilizing a carbon composite base material, the carbon composite base material including a carbon base material; and an iron layer. The iron layer, to which a metal material can be joined, is formed on a surface of the carbon base material, iron powders, which are used to form the iron layer, are subjected to a treatment so as to increase surface-adsorbed oxygen before placing the iron powders to the surface of the carbon base material that is formed in advance by sintering, and sintering is applied to the iron powders placed on the surface of the carbon base material at a temperature not less than a diffusion temperature of carbon and not more than a melting point of iron in order to form the iron layer on the surface of the carbon base material.

Abstract: In the semiconductor device according to the present invention, a P type diffusion layer and an N type diffusion layer as a drain lead region are formed on an N type diffusion layer as a drain region. The P type diffusion layer is disposed between a source region and the drain region of the MOS transistor. When a positive ESD surge is applied to a drain electrode, causing an on-current of a parasite transistor to flow, this structure allows the on-current of the parasite transistor to take a path flowing through a deep portion of an epitaxial layer. Thus, the heat breakdown of the MOS transistor is prevented.

Abstract: The invention provides a DMOS transistor in which a leakage current is decreased and the source-drain breakdown voltage of the transistor in the off state is enhanced when a body layer is formed by oblique ion implantation. After a photoresist layer 18 is formed, using the photoresist layer 18 and a gate electrode 14 as a mask, first ion implantation is performed toward a first corner portion 14C1 on the inside of the gate electrode 14 in a first direction shown by an arrow A?. A first body layer 17A? is formed by this first ion implantation. The first body layer 17A? is formed so as to extend from the first corner portion 14C1 to under the gate electrode 14, and the P-type impurity concentration of the body layer 17A? in the first corner portion 14C1 is higher than that of a conventional transistor.

Abstract: This invention provides a DMOS transistor that has a reduced ON resistance and is prevented from deterioration in strength against an electrostatic discharge. An edge portion of a source layer of the DMOS transistor is disposed so as to recede from an inner corner portion of a gate electrode. A silicide layer is structured so as not to extend out of the edge portion of the source layer. That is, although the silicide layer is formed on a surface of the source layer, the silicide layer is not formed on a surface of a portion of a body layer, which is exposed between the source layer and the inner corner portion of the gate electrode. As a result, the strength against the electrostatic discharge can be improved, because an electric current flows almost uniformly through whole of the DMOS transistor without converging.

Abstract: A conventional semiconductor device has a problem that an on-current of a parasitic transistor flows through a surface portion of a semiconductor layer and thus a semiconductor element undergoes thermal breakdown. In a semiconductor device according to the present invention, a protection element is formed with use of an isolation region and N type buried layers. A PN junction region in the protection element is formed on a P type buried layer of the isolation region. The PN junction region has a junction breakdown voltage lower than that of a PN junction region of a semiconductor element to be protected. This structure allows an on-current of a parasitic transistor to flow into the protection element, and thereby the semiconductor element is protected. In addition, the on-current of the parasitic transistor flows through a deep portion of the epitaxial layer, and thereby the protection element is prevented from thermal breakdown.

Abstract: In a semiconductor device of the present invention, an N type epitaxial layer is divided into a plurality of element formation regions by an isolation region. In one of the element formation regions, an NPN transistor is formed. Around the NPN transistor, a protection element having a PN junction region is formed. The PN junction region has a junction breakdown voltage lower than that of a PN junction region of the NPN transistor. By use of this structure, when negative ESD surge is applied to a pad for a base electrode, the PN junction region of the protection element breaks down. Accordingly, the NPN transistor can be protected.

Abstract: Disclosed is that in a method of manufacturing a semiconductor device of the present invention, when first and second P type diffusion layers using as a backgate region, these layers are formed in such a way that their impurity concentration peaks are shifted, respectively. Then, in the backgate region, a concentration profile of a region where an N type diffusion layer is formed is gradually established. After that, impurity ions, which form the N type diffusion layer, are implanted, and thereafter a thermal treatment is performed to diffuse the N type diffusion layer in a y shape at a lower portion of a gate electrode. This manufacturing method makes it possible to implement an electric filed relaxation in a drain region.

Abstract: An ON resistance of a trench gate type transistor and a withstand voltage of a planar type transistor are optimized at the same time. Each of first and second regions of a semiconductor layer is formed by epitaxial growth on each of first and second regions of a semiconductor substrate, respectively. A first buried layer is formed between the first region of the semiconductor substrate and the first region of the semiconductor layer, while a second buried layer is formed between the second region of the semiconductor substrate and the second region of the semiconductor layer. The first buried layer is formed of an N+ type first impurity-doped layer and an N type second impurity-doped layer that extends beyond the fist impurity-doped layer. The second buried layer is formed of an N+ type impurity-doped layer only. In the first region of the semiconductor layer, an impurity is diffused from a surface of the semiconductor layer deep into the semiconductor layer to form an N type third impurity-doped layer.

Abstract: This invention provides a DMOS transistor that has a reduced ON resistance and is prevented from deterioration in strength against an electrostatic discharge. An edge portion of a source layer of the DMOS transistor is disposed so as to recede from an inner corner portion of a gate electrode. A silicide layer is structured so as not to extend out of the edge portion of the source layer. That is, although the silicide layer is formed on a surface of the source layer, the silicide layer is not formed on a surface of a portion of a body layer, which is exposed between the source layer and the inner corner portion of the gate electrode. As a result, the strength against the electrostatic discharge can be improved, because an electric current flows almost uniformly through whole of the DMOS transistor without converging.

Abstract: A breakdown voltage of a clamp diode can be reduced while a leakage current is suppressed. A P? type diffusion layer is formed in a surface of an N? type semiconductor layer. An N+ type diffusion layer is formed in a surface of the P? type diffusion layer. A P+ type diffusion layer is formed adjacent the N+ type diffusion layer in the surface of the P? type diffusion layer. An N+ type diffusion layer is formed adjacent the P? type diffusion layer in the surface of the N? type semiconductor layer. There is formed a cathode electrode, which is electrically connected with the N+ type diffusion layer through a contact hole formed in an insulation film on the N+ type diffusion layer. There is formed a wiring (an anode electrode) connecting between the P+ type diffusion layer and the N+ type diffusion layer through a contact hole formed in the insulation film on the P+ type diffusion layer and a contact hole formed in the insulation film on the N+ type diffusion layer.

Abstract: In a semiconductor device of the present invention, a thin gate oxide film is formed on a P-type diffusion layer. On the gate oxide film, a gate electrode is formed. N-type diffusion layers are formed in the P-type diffusion layer, and the N-type diffusion layer is used as a drain region. The N-type diffusion layer is diffused in a ? shape at least below the gate electrode. With the structure described above, a diffusion region of the N-type diffusion layer expands and comes to be a low-concentration region in the vicinity of a surface of an epitaxial layer. Thus, it is possible to reduce an electric field from the gate electrode and an electric field between a source and a drain.

Abstract: A method of fabricating a semiconductor device includes a first step of forming a defect suppression film suppressing increase in a defect due to implantation of an impurity on a semiconductor substrate, a second step of forming an active region on a surface of the semiconductor substrate by implanting the impurity through the defect suppression film, a third step of removing the defect suppression film and a fourth step of forming an interface state suppression film suppressing increase in an interface state density of the active region on the active region.

Abstract: In a semiconductor device of the present invention, an N type epitaxial layer is formed on a P type single crystal silicon substrate. The substrate and the epitaxial layer are partitioned into a plurality of element formation regions by isolation regions. Each of the isolation regions is formed of a P type buried diffusion layer and a P type diffusion layer coupled thereto. The P type buried diffusion layer is joined to N type buried diffusion layers on both sides thereof to form PN junction regions. On the other hand, the P type diffusion layer is joined to N type diffusion layers on both sides thereof to form PN junction regions. This structure suppresses extension of widthwise diffusion of the P type buried diffusion layer and the P type diffusion layer, thus making it possible to reduce the device size.

Abstract: A semiconductor device includes a gate electrode formed through an insulating film in a groove having a first side surface adjacent to a source region and a base region, and a second conductive type first impurity region formed adjacent to a second side surface of the groove between the groove and a lead-out portion of a drain region existing below the base region so as to extend downward beyond a lower end of the groove.

Abstract: A commutator utilizing a carbon composite base material, the carbon composite base material including a carbon base material; and an iron layer. The iron layer, to which a metal material can be joined, is formed on a surface of the carbon base material, iron powders, which are used to form the iron layer, are subjected to a treatment so as to increase surface-adsorbed oxygen before placing the iron powders to the surface of the carbon base material that is formed in advance by sintering, and sintering is applied to the iron powders placed on the surface of the carbon base material at a temperature not less than a diffusion temperature of carbon and not more than a melting point of iron in order to form the iron layer on the surface of the carbon base material.

Abstract: A semiconductor device includes a trench formed in a surface of a semiconductor substrate. A conductor is embedded in the trench. A conductive layer is arranged adjacent to the trench on the surface of the semiconductor substrate. Semiconductor elements, which include sources provided by one of the conductor and the conductive layer and drains provided by the other one of the conductor and the conductive layer, are formed in a semiconductor element formation region. A planar wiring layer is embedded in the semiconductor substrate under the entire semiconductor element formation region and connected to the conductor.

Abstract: In a conventional semiconductor device, for example, a MOS transistor, there is a problem that a parasitic transistor is prone to be operated due to an impurity concentration in a back gate region and a shape of diffusion thereof. In a semiconductor device of the present invention, for example, a MOS transistor, a P type diffusion layer 5 as the back gate region, and an N type diffusion layer 8 as a drain region, are formed in an N type epitaxial layer 4. In the P type diffusion layer 5, an N type diffusion layer 7 as a source region and a P type diffusion layer 6 are formed. The P type diffusion layer 6 is formed by performing ion implantation twice so as to correspond to a shape of a contact hole 15. Moreover, impurity concentrations in surface and deep portions of the P type diffusion layer 6 are controlled. By use of this structure, a device size is reduced, and an operation of a parasitic NPN transistor is suppressed.

Abstract: The invention is directed to providing an electrostatic breakdown protection circuit having an enhanced performance of protecting an internal circuit from a surge voltage such as static electricity (an operation speed or resistance to electrostatic breakdown). An N-channel type MOS transistor is connected between a wiring and a VSS (ground voltage) wiring. A first capacitor is connected between the wiring and a gate of the MOS transistor, and a second capacitor is connected between the VSS wiring and the gate. A voltage applied to an input/output terminal is divided by these capacitors, and the divided voltage is applied to the gate. When a surge voltage occurs, the MOS transistor is forced to turn on by the divided voltage to flow a current, thereby protecting an internal circuit. When a larger surge voltage occurs, a parasitic bipolar transistor turns on. A Zener diode is disposed between the gate and the VSS wiring in order to prevent a voltage applied to the gate from exceeding a predetermined voltage.

Abstract: In a semiconductor device of the present invention, an N type epitaxial layer is divided into a plurality of element formation regions by an isolation region. In one of the element formation regions, a resistance is formed. Around the resistance, a protection element having a PN junction region is formed. The PN junction region has a junction breakdown voltage lower than that of a PN junction region of the resistance. By use of this structure, when negative ESD surge is applied to a pad for an electrode which applies a voltage to a P type diffusion layer, the PN junction region of the protection element breaks down. Accordingly, the resistance can be protected.

Abstract: In a conventional semiconductor device, there is a problem that an N-type diffusion region provided for protecting an element from an overvoltage is narrow and a breakdown current is concentrated so that a PN junction region for protection is broken. In a semiconductor device of the present invention, an N-type buried diffusion layer is formed across a substrate and an epitaxial layer. A P-type buried diffusion layer is formed across a wider region on an upper surface of the N-type buried diffusion layer so that a PN junction region for overvoltage protection is formed. A P-type diffusion layer is formed so as to be connected to the P-type diffusion layer. A breakdown voltage of the PN junction region is lower than a breakdown voltage between a source and a drain. With this structure, the concentration of the breakdown current is prevented so that the semiconductor device can be protected from the overvoltage.