| 摘要 |
PURPOSE:To improve an S/N ratio by a method wherein an insulation film with an even thickness comprising cadmium tellurate of a uniform composition is provided on an interface between a cathode electrode and a compound semiconductor and checks the injection of electrons from the cathode electrode evenly to obtain a dark current low sufficiently in a stable manner. CONSTITUTION:A substrate 1 comprising a high resistance CdTe semiconductor crystal doped with chlorine is ground on both sides thereof and a modified layer caused by working is etched away. An In metal layer is formed as anode electrode 2 on one main surface of the substrate 1 by vacuum evaporation film method. The electrode 2 employs a metal element with electric barrier thereof high against holes, for example, Ga or Al. A uniform insulation film 3 comprising CdTeO3 is formed on the surface of the substrate 1 except for the portion where the electrode 2 is formed by thermal oxidation in an atmosphere of oxygen. Then, an Au layer with electric barrier high against electrons is formed on the insulation film 3 of the other main surfaces of the substrate 1 facing the electrode 2 as cathode electrode 4 by vacuum evaporation method. The substrate 1 containing the electrodes 2 and 4 and the insulation film 3 is cut off to complete a radiation detector 5.
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