ELECTROCHEMICALLY ETCHED MULTILAYER SEMICONDUCTOR STRUCTURES

Abstract

An electrochemical method is disclosed for selectively etching either n-type or p-type semiconductor material in the presence of the other type. A liquid electrolyte is prepared in which the etching reaction is based on hole transport. In selectively etching p-type material the holes are provided by the dopant concentration and the process is carried out in the dark to prevent the etching of n-type layers. Conversely, selective etching of n-type material is done in the presence of light and with p-type material effectively out of the current path. In a preferred embodiment of a method of selectively etching a doping superlattice n-i-p-i structure composed of alternating p-type and n-type GaAs layers, C6 H2 (OH)2 (SO3 Na)2 •H2 O is used as the electrolyte. Selectively etching first the p-type layers at one end of the structure and then the n-type layers at the other end, digitate edge patterns are etched to which ohmic contacts can be applied. The invention also encompasses selectively etched structures which can be used to fabricate various kinds of electro-optic devices, such as optical modulators and photodetectors.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1WEI-YU WU

Sensitive facility: El Segundo CA (Aerospace Corp/TRW)

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