Hitachi, Ltd.

Yohei Yanagida

Shinichiro Wada

Tomoyuki Miyoshi

Takayuki Oshima

Kenji Miyakoshi

Hiroki Kimura

Keigo Kitazawa

Adverse effects can be hardly exerted on a current performance of an LDMOSFET to suppress the amount of carrier implantation from an anode layer of an LDMOS parasitic diode, and improve a reverse recovery withstand of the parasitic diode. The LDMOSFET includes a semiconductor substrate having a first semiconductor region formed of a feeding region of a first conductivity type at a position where a field oxide film is not present on a surface layer of a semiconductor region in which the field oxide film is selectively formed, and a second semiconductor region formed of a well region of a second conductivity type which is an opposite conductivity type, and feeding regions of the first conductivity type and the second conductivity type formed on an upper layer of the well region, and a gate electrode that faces the well region through a gate oxide film. The feeding region of the first semiconductor region is formed at a distance from the field oxide film near an end portion remote from the gate electrode, and desirably the feeding region is intermittently formed at intervals in the longitudinal direction.

Semiconductor device

In an LDMOS transistor, a channel length is reduced to increase a saturation current without causing an off-state breakdown voltage optimized in terms of trade-off between an on-resistance and the off-state breakdown voltage. A short channel region is selectively formed between an element isolation film and a low-concentration body region in which a channel is formed such that the short channel region is located immediately below a gate oxide film. The short channel region has a conduction type opposite to that of the low-concentration body region and has a carrier concentration higher than that of the low-concentration body region. The body region is retreated by the presence of the short channel region toward a high-concentration source region.

Semiconductor device and its manufacturing method

A high voltage ESD protective diode having high avalanche withstand capability and capable of being formed by using manufacturing steps identical with those for a high voltage transistor to be protected, the device having a structure in which a gate oxide film is formed over a substrate surface at a PN junction formed of an N type low concentration semiconductor substrate constituting a cathode region and a P type low concentration diffusion region constituting an anode region, and a gate electrode which is disposed overriding the gate oxide film and a field oxide film is connected electrically by way of a gate plug with an anode electrode, whereby an electric field at the PN junction is moderated upon avalanche breakdown to obtain a high avalanche withstand capability. Further, the withstand voltage can be adjusted by changing the length of the field oxide film.

Method of manufacturing semiconductor device having high voltage ESD protective diode

The cell size is reduced and device reliability is improved for a semiconductor device including plural transistors making up a multi-channel output circuit. In a multi-channel circuit configuration, a group of transistors having a common function of plural channels are surrounded by a common trench for insulated isolation from another group of transistors having another function. The collectors of mutually adjacent transistors on the high side are commonly connected to a VH power supply, whereas the emitters of mutually adjacent transistors on the low side are commonly connected to a GND power supply.

Growing community of inventors

Hamura, Japan

Yohei Yanagida