METHOD OF MANUFACTURING AN INFRA-RED DETECTOR DEVICE

摘要

PHB 32578 24 28.8.80 Method of manufacturing an infra-red detector device. In the manufacture of an infra-red detector device at least a portion of a surface of a body (4) of mercury cadmium telluride is subjected to a conversion treatment (for example, using electrolytic anodising or a chemical oxidizing solution such as H202) to produce a surface layer (7), after which a heating step is performed. The invention provides a simple and reproducible process for forming in the body a p-n junction (10) of sufficiently good quality for such a detector which can be of planar form so facilitating the formation of detector element arrays in the body and the provision of contacts to the detector element(s). The layer (7) produced by the conversion treatment comprises a sufficient quantity of an element (apparently mercury) derived from said body (4) as to act subsequently as a source for re-introducing said element into said body (4). This constituent element of said body (4) when present in an excess concentration in the material of said body (4) yields the characteristics of n-type material at the operating temperature of the detector device (for example room temperature OR 77.degree.K). The surface layer (7) is heated in said heating step to a temperature in excess of 100.degree.C (for example in the range of 125.degree.C to 270.degree.C for a period in the range of 100 seconds to 40 hours) to introduce a quantity of said element from the surface layer (7) into an underlying region (9) of the body (4) so as to form the p-n junction (10). Preferably the surface layer (7) is produced on mercury cadmium telluride which has at said device operating temperature the characteristics of p-type material. However it is also possible for at least a surface portion to be n-type and to be converted to p-type material by said heating step which also forms the n-type region (9) from the layer (7).