TRANSISTOR, VHF, SILICON, POWER (50W - 150MC).
Abstract
The transistor was designed on the principle of paralleling a group of small transistor cells to build up to the required power. Three basic designs were made in the course of optimizing the RF and thermal performance of the device. Equalizing the base feed to each cell was determined to be a critical factor in getting all the cells to work together. An important feature of the cell structure is that an individual cell which exhibits poor characteristics can be disconnected from the pattern by photoresist techniques, a potent factor in keeping production yields high. Two new processes are worthy of note. The first is the evaporation of metal contacts over oxide layers in sufficient thickness to conduct the required current. The second is the deposition of oxide layers by the decomposition of ethyl silicate, which served to preclude holes in the grown oxide layers due to imperfections in the photoresist masks or other causes. The package which was finally used for the transistor samples was a beryllia disk package which had demonstrated its reliability and performance on a commercially available 5W-250mc transistor (PT2600). With the 50W-150mc transistor crystal the package was shown to be capable of dissipating 125 watts. A significant feature of the program was the coordinated development of the device-circuit combination to give optimal total performance of the 50W, 150mc circuit block. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1964
- Accession Number
- AD0615127
Entities
People
- B. Rappaport
- M. O. Preletz
- S. H. Barnes