SEMICONDUCTOR RADIATION DETECTOR AND ITS MANUFACTURE

• Main Author: OZAKI TSUTOMU
• Format: Patent
• Language: English
• Published: 06.06.1997
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MEASUREMENT OF NUCLEAR OR X-RADIATION; MEASURING; PHYSICS; SEMICONDUCTOR DEVICES; TESTING

PROBLEM TO BE SOLVED: To reduce a dark current by installing an anode electrode constituted of metal having a high barrier to positive holes which metal is arranged on an insulating film having specified TeO2 component which film is formed on the surface of a compound semiconductor substrate whose main component is CdTe, and a cathode electrode constituted of metal having a high barrier to electrons which metal is arranged on the back of the board. SOLUTION: Both surfaces of a substrate which is composed of chlorine doped high resistance CdTe semiconductor single crystal and has face orientation (111) are ground. A worked denatured layer generated by polishing is eliminated by etching. After approximate metal Te layers wherein the ratio of Te is more excessive than that of Cd are formed on the surface and the back of the CdTe substrate, thermal oxidization is performed in oxygen atmosphere, and oxidized films wherein TeO2 component is 96% (higher than or equal to 90%) are formed. Indium is evaporated on the (111) B surface side of the substrate and turned into an anode electrode. Electroless plating of gold is performed on the (111) A surface side which is opposite to the indium electrode surface, and a cathode electrode is formed. Since the oxidized film wherein the ratio of Te is more excessive than that of Cd is formed on the interface between the anode electrode and the CdTe substrate, a dark current can be reduced on the anode electrode forming surface.