Sanyo Electric Co., Ltd.

Yumiko Akaishi

Shuichi Kikuchi

Takuya Suzuki

Shinya Mori

Yuji Tsukada

Yuichi Watanabe

In order to improve the characteristics of the high breakdown voltage MOS, a semiconductor device of the present invention is characterized in that an LDMOS transistor, which comprises a source region, a channel region, and a drain region, and a gate electrodeformed on the channel region, and a drift region formed between the channel regionand the drain region, wherein an N-type low concentration layerserving as the drift region is formed shallowly at least below the gate electrode(first N-type layerA) but formed deeply in a neighborhood of the drain region(second N-type layerB).

Semiconductor device and method of manufacturing the same

To enhance the withstand voltage of an LD MOS transistor, a method of fabricating a semiconductor device according to the invention is characterized in that a process for forming a drift region is composed of a step for implanting phosphorus ions and arsenic ions different in a diffusion coefficient into the superficial layer of a substrate, a step for forming a selective oxide film (a first gate insulating film) 9A and an element isolation film 9B by selective oxidation and diffusing the phosphorus ions and the arsenic ions and a step for implanting and diffusing boron ions, and in that in the step for forming the selective oxide film 9A and the element isolation film 9B by selective oxidation in a state in which an oxide film and a polycrystalline silicon film are laminated on the substrate, only a drift region formation region is selectively oxidized in a state in which the polycrystalline silicon film is removed.

Semiconductor device and method of fabricating thereof

Disclosed is a method of manufacturing a semiconductor device which includes a source region, a channel region, a drain region, a gate electrode formed on the channel region through a gate insulating film,and a drift region (N,layer,) formed between the channel region and the drain region, wherein the process of forming the drift region (N,layer) comprises the steps of: ion-implanting and diffusing at least two kinds of second conduction type impurities (e.g. phosphorus and arsenic ions) having different diffusion coefficients in a P-type well region,; ion-implanting at least one kind first conduction type impurities (e.g. boron ions) having a diffusion coefficient substantially equal to or larger than that of at least one of said second conduction type impurities (e.g. phosphorus); and diffusing the first conduction type impurities after the gate insulating film,has been formed.

Growing community of inventors

Gunma, Japan

Yumiko Akaishi