| 摘要 |
PURPOSE:To enable to control the lifetime of minority carrier by a method wherein a semiinsulating film having high trap density is formed on a semiconductor substrate, thereby enabling to prevent the deterioration of junction withstand voltage. CONSTITUTION:A semiinsulating polycrystalline silicon film 32 containing approximately 30 atomic% of oxygen, for example, is directly formed on the surface of a semiconductor substrate 22 having one or more of P-N junctions or Schottky junctions by performing a CVD method, and then the insulating film 33 such as a silicon dioxide film and the like is formed by performing an ordinary CVD method. Subsequently, after an electrode wiring layer and a protective film 36 have been formed, the specific dose of radioactivity of radiant rays having the high energy of 0.5MeV or above are made to irradiate on the whole surface. The positive electric charge in the semiinsulating film 32 generated by the above-mentioned irradiation is caught in trap level, and it runs in the film as a carrier. Consequently, as the positive electric charge is not left in the film as a fixed electric charge, it gives no influence on the variation of the carrier density of the substrate surface. Accordingly, the lifetime of minority carrier can be controlled property without deteriorating the junction withstand voltage.
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