Accession Number : AD0622879

Title :   TRANSISTOR, VHF, SILICON, POWER (10W-500MC).

Descriptive Note : Final rept. for 1 Jul 63-15 Jan 65,

Corporate Author : TRW SEMICONDUCTORS INC LAWNDALE CALIF RESEARCH AND DEVELOPMENT DEPT

Personal Author(s) : Clarke,R. N. ; Crishal,J.

Report Date : 15 JAN 1965

Pagination or Media Count : 120

Abstract : The transistor produces 10 watts at 500 mc with 5-6 db of power gain and 30-40% collector efficiency. The crystal was originally designed according to present power gain theory, but it only had one to two db of power gain at 500 mc. The second crystal design was based upon the smallest practical pattern dimensions, or a 0.1 mil minimum spacing. The redesigned pattern also had provision for analyzing the transistor in multiples of sub cells as well as in its entirety. Such an analysis showed the necessity of symmetry of base feed in common emitter amplifiers to get all the cells working together. Paralleling of cells also indicated an apparent loss in f sub T with increased size. Processing and assembly was generally along standard industry practice except in the area of photoresist. There, improved glass masks were used, along with the new KTFR photoresist. Successful etching of fine metallized patterns was accomplished through the development of a jet etching technique. To retain as much of the innate crystal performance capability as possible, considerable work was done on packaging. It was concluded that no available package was truly adequate. The best available for the R.F. performance is the silicone molded package due to its short, low-loss leads. This package has a bonus of reliability and ruggedness as well as a large cost reduction in eventual production. (Author)

Descriptors :   (*TRANSISTORS, SILICON), VERY HIGH FREQUENCY, RADIOFREQUENCY POWER, CRYSTALS, PROCESSING, PACKAGING, CHEMICAL MILLING, DIFFUSION, SILICONE PLASTICS, VAPOR PLATING, METAL FILMS

Distribution Statement : APPROVED FOR PUBLIC RELEASE