Hitachi, Ltd.

Kenji Miyakoshi

Takayuki Oshima

Shinichiro Wada

Yohei Yanagida

Junji Noguchi

Masaya Iida

Hiroki Kimura

Tomoyuki Miyoshi

Koichiro Miyamoto

Masafumi Suefuji

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

When MOS transistors having a plurality of threshold voltages in which a source and a drain form a symmetrical structure are mounted on the same substrate, electrically-symmetrical characteristics is provided with respect to an exchange of the source and the drain in each MOS transistor. A MOS transistor having a large threshold voltage is provided with a halo diffusion region, and halo implantation is not performed on a MOS transistor having a small threshold voltage.

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Ome, Japan

Kenji Miyakoshi