JPS6428872A - Semiconductor element for detecting radiation - Google Patents

Abstract

PURPOSE:To prevent the leak current on the surface of a detecting element, by installing a guard ring of adequate structure on the surface of a P-N junction type semiconductor detection element of radiation. CONSTITUTION:By thermal diffusion treatment, a P<+> layer 2, a P<+> layer 3, and a P<+> layer 4 of guard ring are formed on a P-type silicon substrate 1. A silicon protective film 6 is arranged on the whole surface of an N<+> layer 2 side. By photo etching, a part of the silicon protective film 6 is eliminated, and an aluminum electrode 7 electrically connected to the N<+> layer 2 is vapor- deposited. By thermal diffusion method, a P<+> layer 3 is formed on the whole surface opposite to the N<+> layer 2, and thereon an aluminum electrode 8 being an opposite electrode is grounded, by applying a positive bias to the whole surface of the aluminum electrode 7. When the bias is applied, a large depletion layer 5 extends in the P-N junction part of the N<+> layer 2. The growing depletion layer 5 reaches the guard ring 4. The leak current can be prevented, by making the length of the guard ring adequate.