Accession Number : AD0847618

Title :   300C Transformer Rectifier.

Descriptive Note : Interim technical rept. no. 3, 1 Jul-30 Sep 68,

Corporate Author : RCA ELECTRONIC COMPONENTS SOMERVILLE NJ

Personal Author(s) : DiPiazza, J. ; Mayer, A.

Report Date : OCT 1968

Pagination or Media Count : 33

Abstract : Gallium arsenide substrate crystal material, grown in-house, that meets the preliminary specification of less than 10,000 dislocations per sq cm now is readily available in quantity. This crystal is sliced parallel to either a <100> plane or a <111> plane but offset 3 degrees toward the nearest <111> or <100> plane, respectively. A clean-up etch that also permits rejection of chemically polished, nonobvious, defective substrate material was introduced just before epitaxial growth. The origin of the defects is partly mechanical. Monitoring the furnace temperature established that the water-vapor transport system requires thirty minutes to reach thermal equilibrium and also that blanket gas flow during this period affects the surface character of the substrates. A new operating schedule was determined. The temperature profile of the hydride system was unstable and corrective action was taken, but epitaxial layers were only about 60 percent smooth. A detailed survey and analysis of commercial packages show that none will meet the requirements for the 300C rectifier. A modified stud package was designed and a trial lot ordered. The pellet will be bonded between two special alloy shoes. The shoe-pellet structure was designed to minimize thermal stresses resulting from CTE mismatch. The apparatus for diffusion bonding was assembled and mechanically tested. (Author)

Descriptors :   (*CRYSTAL RECTIFIERS, MANUFACTURING), GALLIUM ARSENIDES, SUBSTRATES, EPITAXIAL GROWTH, DOPING, TELLURIUM, HYDRIDES, HIGH TEMPERATURE.

Subject Categories : Electrical and Electronic Equipment
      Mfg & Industrial Eng & Control of Product Sys

Distribution Statement : APPROVED FOR PUBLIC RELEASE