Mitsubishi Denki Kabushiki Kaisha

Masana Harada

Tadaharu Minato

Tetsuo Takahashi

Katsumi Nakamura

Hideki Takahashi

Hidenori Nishihara

Katsuhiro Tsukamoto

Kiyoto Watabe

Shinji Aono

Ikunori Takata

A pin diode is formed by a pcollector region, an n type buffer region, an nregion and an ncathode region. A trench is formed from the surface of ncathode region through ncathode region to reach nregion. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of ncathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to ncathode region. An anode electrode is formed to be electrically connected to pcollector region. The ncathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.

Semiconductor device and manufacturing method thereof

A plurality of p anode regions are formed at one surface of an nsubstrate. A trench is formed in each p anode region. An ohmic junction region is formed between an anode metallic electrode and the p anode region. The p anode region has a minimum impurity concentration at a portion near the ohmic junction region which enables ohmic contact. A cathode metallic electrode is formed at the other surface of the nsubstrate with an ncathode region interposed. Accordingly, a semiconductor device which has an improved withstand voltage and in which the reverse recovery current is reduced can be obtained.

Semiconductor device and method of manufacturing thereof

Semiconductor device

A pin diode is formed by a p collector region, an n type buffer region, an n region and an n cathode region. A trench is formed from the surface of n cathode region through n cathode region to reach n region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n cathode region. An anode electrode is formed to be electrically connected to p collector region. The n cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.

A plurality of p anode regions are formed at one surface of an n substrate. A trench is formed in each p anode region. An ohmic junction region is formed between an anode metallic electrode and the p anode region. The p anode region has a minimum impurity concentration at a portion near the ohmic junction region which enables ohmic contact. A cathode metallic electrode is formed at the other surface of the n substrate with an n cathode region interposed. Accordingly, a semiconductor device which has an improved withstand voltage and in which the reverse recovery current is reduced can be obtained.

An insulated gate semiconductor device in which the ON voltage is decreased by providing strip like trenches (,) having gate electrodes (,) buried therein are formed in an upper main surface of a semiconductor base body (,), and an N,emitter layer (,) is exposed in a ladder-like form in the upper main surface of the semiconductor base body interposed between adjacent trenches (,). Accordingly, even if the position of a zonal region (Ra) which is a contact surface with an emitter electrode (,) is shifted, the emitter electrode (,) is surely in contact with the N,emitter layer (,). Furthermore, the ladder-like N,emitter layer (,) is formed adjacent to the trench (,), so that a channel region (,) is formed without discontinuation along the trench (,). Accordingly, it has the effect of facilitating miniaturization of elements and of effectively making use of the miniaturization to decrease the ON voltage.

Insulated gate semiconductor device and manufacturing method thereof

A pin diode is formed by a p,collector region, an n type buffer region, an n,region and an n,cathode region. A trench is formed from the surface of n,cathode region through n,cathode region to reach n,region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n,cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n,cathode region. An anode electrode is formed to be electrically connected to p,collector region. The n,cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.

An anode electrode metal layer composed of aluminum is formed in a region on the inner side than an anode layer formed on a main surface of a semiconductor substrate. Thus, an impurity diffusion region from the innermost circumferential surface of said surface of field limiting innermost circumferential layer to the outermost circumferential surface of the anode electrode metal layer may be used as an electrical resistance. As a result, the hole density distributed from the bottom side of the field limiting innermost circumferential layer to a cathode layer when forward bias is applied may be reduced. As a result, when a reverse bias is applied, locally great recovery current passed from a cathode layer to the bottom of field limiting innermost circumferential layer may be restrained. Therefore, a diode capable of preventing destruction of a field limiting innermost circumferential layer when a reverse bias is applied may be provided.

Free wheel diode for preventing destruction of a field limiting innermost circumferential layer

An insulated gate semiconductor device in which the ON voltage is decreased by providing strip like trenches (207) having gate electrodes (210) buried therein are formed in an upper main surface of a semiconductor base body (200), and an N.sup.+ emitter layer (206) is exposed in a ladder-like form in the upper main surface of the semiconductor base body interposed between adjacent trenches (207). Accordingly, even if the position of a zonal region (Ra) which is a contact surface with an emitter electrode (212) is shifted, the emitter electrode (212) is surely in contact with the N.sup.+ emitter layer (206). Furthermore, the ladder-like N.sup.+ emitter layer (206) is formed adjacent to the trench (207), so that a channel region (208) is formed without discontinuation along the trench (207). Accordingly, it has the effect of facilitating miniaturization of elements and of effectively making use of the miniaturization to decrease the ON voltage.

A pin diode is formed by a p.sup.+ collector region, an n type buffer region, an n.sup.- region and an n.sup.+ cathode region. A trench is formed from the surface of n.sup.+ cathode region through n.sup.+ cathode region to reach n.sup.- region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n.sup.+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n.sup.+ cathode region. An anode electrode is formed to be electrically connected to p.sup.+ collector region. The n.sup.+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.

A semiconductor device which allows an ON-state voltage to be lower than that of a conventional device and a method of manufacturing such a device. In this semiconductor device, a gate electrode is formed to have a planar area of its region covering a first base layer larger than that of its region covering a second base layer, thereby increasing a cathode short-circuit ratio of a cathode-shorted diode equivalent to this semiconductor device. As a result, a lower voltage than conventional ON-state can be obtained.

Semiconductor device having insulated gate bipolar transistor

In an SOI substrate including a single-crystal Si substrate (1b), an oxide film (20) and a single-crystal Si substrate (1a), there is formed an stepped wall surface (8) by selective removal of the single-crystal Si substrate (1a) to provide a thick oxide film (5) on the stepped wall surface (8). When a VDMOS (100) is formed in an active region of the single-crystal Si substrate (1b) above which the single-crystal Si substrate (1a) is absent and an MOS (101) having a thin oxide film (22) is formed in the single-crystal Si substrate (1a), the oxide film (5) is not damaged because it is thick. The thickness of the single-crystal Si substrate (1a) enables to be designed in accordance with the required thickness of the MOS (101).

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Hyogo, Japan

Masana Harada