Abstract: In a semiconductor device including a composite substrate formed by bonding first and second semiconductor substrates to each other through an oxide film and an insulator isolation trench formed from a major surface of the first semiconductor substrate to reach the oxide film and to surround an element forming region, when the potential of the second substrate is set at a potential higher than the minimum potential in the element forming region of the first substrate, an breakdown voltage can be increased. In a semiconductor integrated circuit having an element isolation region, a semiconductor device of a perfect dielectric isolation structure having an element forming region having a thickness smaller than that of the element forming region of a P-N junction isolation structure is used to reduce, e.g., a base curvature influence, thereby obtaining a further high breakdown voltage.

Abstract: A vertical MOSFET includes a trench whose inner surface is covered with an insulating layer having a multilayer structure. In order to reduce a change in a gate threshold voltage, and equivalent silicon dioxide thickness of the gate insulating layer and a radius of curvature of an upper corner of the trench are provided such that a dielectric breakdown electric field strength of the gate insulating layer at the upper corner is in the range of 2.5 MV/cm to 5.0 MV/cm.

Abstract: A power MOS semiconductor device, such as a vertical MOSFET, IGBT, and IPD, includes a body of semiconductor material having a first semiconductor layer having a first conductivity type, a second semiconductor layer having a second conductivity type and formed in the first semiconductor layer to provide a channel, a third semiconductor layer having the first conductivity type and formed in the second semiconductor layer, a trench formed in the first semiconductor layer across the third and second semiconductor layers, a gate insulating film covering a surface of the trench and extending to a surface of the third semiconductor layer, a gate electrode layer provided on the gate insulating film, and a buried layer having the first conductivity type provided in the first semiconductor layer so as to be contiguous to a bottom of the trench.

Abstract: A vertical MOS transistor comprises a semiconductor substrate, a first impurity region defined on the surface of the semiconductor substrate, a second impurity region defined under the first impurity region, the conduction type of the second impurity region being opposite to that of the first impurity region, a trench engraved on the surface of the semiconductor substrate to cut through the first and second impurity regions deeper than at least the bottom of the second impurity region, and a gate electrode disposed in the trench with a gate insulation film interposing between the wall of the trench and the gate electrode. The gate insulation film is thicker on the bottom of the trench and on part of the side walls of the trench continuous to the bottom than on the other parts.

Abstract: A vertical MOS transistor comprises a semiconductor substrate, a first impurity region defined on the surface of the semiconductor substrate, a second impurity region defined under the first impurity region, the conduction type of the second impurity region being opposite to that of the first impurity region, a trench engraved on the surface of the semiconductor substrate to cut through the first and second impurity regions deeper than at least the bottom of the second impurity region, and a gate electrode disposed in the trench with a gate insulation film interposing between the wall of the trench and the gate electrode. THE gate insulation film is thicker on the bottom of the trench and on part of the side walls of the trench continuous to the bottom than on the other parts.

Abstract: A first insulative film is formed with predetermined height and thickness in a loop shape on the surface of the Schottky-junction semiconductor substrate. A gate electrode metal film is formed with a predetermined height and thickness in a loop shape on the surface of the substrate along the inner surface of the first insulative film. A second insulative film is formed with a predetermined height and thickness in a loop shape on the surface of the substrate along the inner surface of the metal film. A channel consisting of a low concentration impurity layer, is formed in a loop shape inside the substrate directly under the metal film and the first and second insulative films. The source region consists of a high-concentration impurity layer formed such that it surrounds the channel positioned inside the substrate on the outside of the first insulative film.

Abstract: A semiconductor device which has a protective film having a high blocking capacity against contaminating ions and a high shielding effect against an external electric field. The protective film is formed on a surface of the semiconductor device. The protective film consists essentially of an amorphous or polycrystalline silicon carbide which contains at least one element selected from the group consisting of hydrogen, nitrogen, oxygen and a halogen.

Abstract: A semiconductor device comprising a high voltage withstanding vertical MOSFET and a low voltage withstanding element both formed on a single chip. A buried layer of a high impurity concentration is formed in a region where the vertical MOSFET is formed, and another buried layer of a high impurity concentration is formed in a region where the low voltage withstanding element is formed. These buried layers have different thickness, whereby the series resistance of a circuit adjacent to the vertical MOSFET is reduced without lowering the withstand voltage of the vertical MOSFET.

Abstract: A method of manufacturing a semiconductor device which comprises the step of applying a silicon carbide film having a prescribed perforated pattern as a masking film selectively to etch a silicon dioxide film or diffuse an impurity into a substrate.

Abstract: A semiconductor device comprising a substrate means, a semiconductor layer of an N conductivity type formed on the substrate means, a first semiconductor region of a P conductivity type formed in the semiconductor layer and having its exposed major surface, a second semiconductor region of the N conductivity type formed in the first semiconductor region and having its exposed major surface, a first insulation layer means having a positive polarity type of charge and formed on the N semiconductor layer, and a second insulation layer means having a negative polarity type of charge and formed on the P semiconductor region.

Abstract: A method of manufacturing a GaAs FET is disclosed. In this manufacturing method, a protection film is formed on a GaAs substrate and a dummy gate electrode is formed thereon. A channel length setting film is isotropically formed on the dummy gate electrode to have a constant thickness. Then, an impurity is ion-implanted in the channel length setting film. Thereafter, the channel length setting film is removed. An etching preventive film is anisotropically formed along a substantially vertical direction with respect to the GaAs substrate. The dummy gate electrode is etched using the etching preventive film as a mask so as to form a first opening in the etching preventive film. Then, a second opening is formed in the region of the protection film corresponding to the region in which the dummy gate electrode was present. A gate electrode is formed to be in contact with the GaAs substrate through the first and second openings.

Abstract: A process for producing a semiconductor device by which the minority carrier lifetime can be selectively changed in a semiconductor device. A radiation beam is irradiated onto the surface of a semiconductor substrate to shorten the minority carrier lifetime. Then ions are selectively implanted into a region in which the minority carrier lifetime is to be recovered. Finally, the resultant structure is annealed.

Abstract: A semiconductor memory device is disclosed which comprises:a semiconductor substrate of n conductivity type;source and drain regions of p.sup.+ conductivity type formed in the substrate;a first gate insulation film of silicon dioxide (SiO.sub.2) formed on the substrate; anda second gate insulation film of silicon carbide (SiC) formed on the first gate insulation film.

Abstract: A semiconductor device comprises a semiconductor body of one conductivity type, at least one semiconductor region of the opposite conductivity type formed in the semiconductor body and having a surface flush with the surface of the semiconductor body, an insulative or semi-insulative film formed on the semiconductor body or semiconductor region through a passivation layer and having a fixed charge, positive or negative, and an electrode metal layer connected to at least one of the semiconductor body and region and formed locally on the film directly or through a passivation layer. The semiconductor body or region is of N conductivity type when the film has a positive fixed charge and of P conductivity type when the film has a negative fixed charge.

Abstract: A method for producing a semiconductor element which can form a deep P-type impurity region by a diffusion of aluminum. A porous alumina layer is first formed on a semiconductor substrate. Then, a diffusion-protective layer formed of a material having a large oxygen-diffusion-inhibiting ability such as Al.sub.2 O.sub.3 is formed on the porous alumina layer. Subsequently, aluminum ions are implanted in the porous alumina layer through the diffusion-protective layer. Thereafter, a heat treatment is performed to diffuse the aluminum of the aluminum ion-implanted region in the semiconductor substrate, and a P-type impurity region is formed. Alternatively, a porous alumina layer is formed on the semiconductor substrate, and an aluminum layer is then formed thereon. The diffusion-protective layer is formed on the aluminum layer, and a heat treatment is then performed, thereby diffusing the aluminum forming the aluminum layer in the semiconductor substrate, and a P-type impurity region is thus formed.

Abstract: A method of manufacturing a semiconductor device, which comprises the steps of forming a first high impurity concentration region of a conductivity type opposite to the conductivity type of a semiconductor substrate in the substrate along the principal surface thereof, depositing a first epitaxial layer of the same conductivity type as the substrate on the entire principal surface thereof, forming a low impurity concentration region of the opposite conductivity type to the substrate in the first epitaxial layer along a surface portion thereof corresponding to the first high impurity concentration region, forming a second high impurity concentration region of the opposite conductivity type to the substrate in the first epitaxial layer along a different surface portion thereof, forming a second epitaxial layer of the opposite conductivity type to the substrate on the first epitaxial layer, thermally treating the resultant intermediate device to cause diffusion of the impurities in the first and second high impu

Abstract: A method of manufacturing a semiconductor device which comprises the step of applying a silicon carbide film having a prescribed perforated pattern as a masking film selectively to etch a silicon dioxide film or diffuse an impurity into a substrate.

Abstract: A semiconductor device comprising a fluorine ion implantation region which is selectively formed in a semiconductor region and further activated. The fluorine ion implantation region is adapted for use as a high resistance layer or electrical isolation layer.

Abstract: There are provided a semiconductor device having alternately layered insulating and conductive layers on the major surface of a semiconductor body and the process for manufacturing the semiconductor device. In the manufacturing process, the conductive layers other than the conductive layer finally formed are each formed to be a laminate including at least two metal layers of which the etching rates are different. The photo-engraving process follows this step. In the lamina, the metal layer closer to the semiconductor body has a lower etching rate than that of the metal layer formed thereover. In the semiconductor device, the conductive layer other than that disposed furthest away from the semiconductor body has its side wall diverged to widen toward the semiconductor body.

Abstract: A method of producing a semiconductor device comprises removing all of the masking films used for forming desired semiconductor regions in the substrate, newly forming an insulation film and selectively forming a second insulation film at predetermined portions by the use of a silicon nitride film as the mask.