Mitsubishi Denki Kabushiki Kaisha

Kenichi Yamanaka

Yutaka Mihashi

Toshio Sogo

Josuke Nakata

A thermo-sensitive semiconductor element having a four-layer pnpn structure. A defect layer is formed at the junction of the p base layer and the n base layer by implantation of argon ions to provide a semiconductor element having a desired thermo-sensitive characteristic. The element is subjected to heat treatment such as annealing at temperatures in a range of from 400.degree. C. to 900.degree. C. in a nitrogen atmosphere after the argon ion implantation so that the leakage current into the element having the defect layer is controlled.

Thermo-sensitive switching element manufacturing method

A planar pnpn thyristor structure is prepared to include an SiO.sub.2 film with a thickness of about 10,000A wholly disposed on its main face to which pn junctions are exposed. That portion of the SiO.sub.2 film underlaid with an exposed edge of a collector junction and its adjacent portion are replaced by another SiO.sub.2 film about 1,000A thick. Then argon ions Ar.sup.+ with an implantation energy of 200 KeV are implanted into the thyristor structure through both films to permit a low lifetime region including a large number of lattice defects to be formed only in its main face portion overlaid with the thin SiO.sub.2 film resulting in a semiconductor thermally sensitive switching element effecting the switchover at a sufficiently low temperature.

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Itami, Japan

Kenichi Yamanaka