Bell Telephone Laboratories

At&t Bell Laboratories

Vassilis G Keramidas

Henryk Temkin

Robert J McCoy

Bulusu V Dutt

Jose A Lourenco

Robert H Saul

Daniel R Cassiday

Ronald J Roedel

Liquid phase epitaxy (LPE) growth of a Group III-V semiconductor compound layer upon a Group III-V semiconductor compound substrate containing phosphorus is accomplished in a graphite meltholder by heating the substrate in an atmosphere of nitrogen or helium and contacting the substrate with a liquid melt, capable of growing the layer, in an atmosphere of hydrogen.

LPE Growth on group III-V compound semiconductor substrates containing

An ohmic contact to a semiconductor device comprising p-type InP is formed by sequentially depositing beryllium-gold and gold layers on InP and then heat-treating the device at a temperature less than 440 degrees C. An ohmic contact to p-type InGaAsP can be similarly formed.

Beryllium-gold ohmic contact to a semiconductor device

Ohmic contact to p-type InP

Indium phosphide stoichiometry in III-V semiconductor devices is sensitive to processing conditions during liquid phase epitaxy deposition. Disclosed is a method for determining indium-to-phosphorus ratio in an n-type indium phosphide semiconductor surface layer by monitoring photoluminescence at an absorption band at or near 0.99 electron volt.

Monitoring indium phosphide surface composition in the manufacture of III-V

A monolithic opto-isolator is fabricated on an insulating substrate by using a graded bandgap semiconductor material for the LED and photodetector and spacing the LED from the photodetector with insulating channels.

Monolithic opto-isolator

A consistently low resistance ohmic contact is made to an aluminum-containing compound semiconductor by a multilayer deposition and heat treatment process. The process includes the deposition of a transition layer on the semiconductor surface to be contacted and an overlying gold layer to provide external contact. The transition layer consists of aluminum and a shallow dopant element which may be deposited as successive layers or together. After the transition layer and the gold overlay are deposited, the composite is raised to a temperature at which the transition layer is liquid. In cases in which the gold-dopant binary system has a polyphase region, it is preferable to select the thickness of the gold layer such that the gold-dopant alloy is in the solid solution region of the phase diagram of that binary system, to prevent enhanced diffusion to the upper gold surface along grain boundaries. In an exemplary realization, an Al-Sn layer was used to contact n-type GaAlAs.

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Warren, NJ, United States of America

Vassilis G Keramidas