Kawasaki Steel Corporation

Yoshihide Tada

Hiroyasu Kunitomo

A projection is formed in a substrate by anisotropic etching and a transistor is contained in the projection. The central portion of the projection covered with a gate electrode is formed as a channel region, and drain and source regions are formed on both sides of the projection by oblique ion implantation with the gate electrode as a mask. Formed below the drain, source, and channel regions is an element isolation section having the composition of the substrate intact. This eliminates the need for an oxide insulating layer below the transistor for easy manufacturing. Carriers generated in the channel region by ionization by collision can also be discharged to the substrate.

Manufacturing method for semiconductor devices with source/drain formed

A semiconductor device of band-to-band tunneling type including a silicon substrate, a first gate electrode formed by a highly doped surface region of the silicon substrate, a first silicon oxide film formed on a surface of the surface region, a silicon thin film formed on the first silicon oxide film, a second silicon oxide film formed on a surface of the thin silicon film, and a second gate electrode formed by a metal film applied on a surface of the second silicon oxide film. In the thin silicon film, there are formed P and N type regions side by side to constitute a PN junction. When a gate bias voltage is applied across the first and second gate electrodes, a band bend having a large height and inclination in a direction perpendicular to the thin silicon film is produced in the depletion region in the vicinity of the PN junction. Minority carriers brought up from the valence band into the conduction band by tunneling due to the band bend are conducted through the PN junction under the influence of a reverse bias voltage applied across the PN junction. The band bend can be made large at will by increasing the gate bias voltage, so that it is possible to obtain a large tunneling current.

Growing community of inventors

Chiba, Japan

Yoshihide Tada