Mitsubishi Denki Kabushiki Kaisha

Ryoden Semiconductor System Engineering Corporation

Satoru Kawazu

Tadashi Nishioka

Chikayuki Okamoto

Norihiko Kotani

Koichi Kijima

Yoshihiko Hirose

Yoshihiko Watari

Isao Inoue

Kousi Nomura

Sidewalls of patterned resist are reformed using a reforming agent selected from the group consisting of (a) a carbon trichloride radical, (b) a mixture of silicon ion and oxygen ion, (c) a mixture of carbon ion and carbon monoxide ion, (d) a chlorine radical, (e) aluminum trichloride liquid and (f) dibutyl magnesium liquid, and sidewall reformed portions are thus formed on the sidewalls of pattern resist. The not reformed portion of the patterned resist is removed away, and sidewall reformed portions are left on an object layer. The portion of object layer excluding the portion immediately below sidewall reformed portions is etched away, and fine patterns of object layer are formed as a result.

Method of forming fine patterns

The disclosed MOS transistor includes a channel region formed of a lightly doped semiconductor layer disposed in a surface portion of a heavily doped semiconductor layer subsequently disposed on a lightly doped semiconductor substrate. The channel region may be of the identical or opposite conductivity type to the heavily doped semiconductor layer that has the same type conductivity as the substrate. Also the channel region may be of an intrinsic semiconductive material. A source and a drain region may be disposed in the lightly or highly doped layer. Alternatively the source and drain regions may reach the substrate.

MOS Semiconductor device

A silicon substrate is selectively implanted with ions and heated in a oxidizing atmosphere. Thus an oxide film is formed on the substrate so that portions of the film formed on regions implanted with the ions is partly embedded in the substrate. Then the film is etched until the surface of the substrate is selectively exposed. An impurity is diffused into the exposed surface portions to form base regions in the substrate after which the process as above described is repeated to form windows for emitter diffusion and electrodes. Also silicon is epitaxially grown on a silicon substrate selectively provided with SiO.sub.2 films so that silicon in the form of a single crystal is grown on the exposed surface portions of the substrate while polycrystalline silicon grown on the SiO.sub.2 films. The above process is repeated to convert the polycrystalline silicon to silicon dioxide for separating the silicon regions on the exposed surface portions from one another.

Process of producing semiconductor devices

Growing community of inventors

Hyogo, Japan

Satoru Kawazu