At&t Bell Laboratories

Bell Telephone Laboratories

James C Hwang

James Vincent DiLorenzo

William Charles Niehaus

Stuart H Wemple

Wolfgang O Schlosser

Strain-free mounting and uniform heating of deposition substrates are achieved by coating the backside of the substrate such as a GaAs substrate with a reflective layer. A reflective environment formed, for example, by tantalum foils allows reflections between the reflective surface of the substrate and the reflective surface of the environment. These multiple reflections, in turn, produce uniform heating of the substrate.

Method of substrate heating for deposition processes

Extremely high-purity and defect-free layers of III-V semiconductor materials are produced by a specific MBE process. This process as applied to GaAs includes protecting the deposition substrate with a passivating surface, removing this surface in situ, treating the bared substrate heated to a temperature below its incongruent melting point with an arsenic-containing gas, and initiating the MBE growth in an environment containing an excess of arsenic over gallium.

III-V Based semiconductor devices and a process for fabrication

GaAs FETs exhibit excellent long-term stability if they have a drain ledge, a drain contact with reduced dendrite size, and a silicon nitride passivation layer. Accelerated aging tests at device case temperatures of 250 degrees C. indicate essentially no device failures after 200 hours of observation and a median failure time of approximately 500 hours.

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Berkeley Heights, NJ, United States of America

James C Hwang