Selective electroless photoetching of n-type InP in acidic solution containing an heteropolyanion (SiMo12O404-)

A new process to locally photoetch n-type InP under electroless conditions is described. It is based on the use of a polyoxometalate, molybdenum heteropolyanion (SiMo12O404-), dissolved in acidic solution, as an oxidizing agent. The etching is confined to where the light is incident to the n-InP surface. The etch rate depends either on the heteropolyanion concentration or on the incident light intensity. The use of SiMo12O404- associated with light also makes it possible to perform dopant-type selective etching because either in the dark or under illumination p-InP does not undergo a dissolution process. This system should also provide a good means for n-InP defect revealing. (C) 2002 Elsevier Science B.V. All rights reserved.