Metal Grid Base Heterojunction Transistor Operating at 60 and 94 GHz
Abstract
This program is for the development of a new device structure, the Metal Gridded Base Heterojunction Transistor (MGBHT). The device is an AlGaAs/ GaAs bipolar structure, and incorporates a metal grid for reduction of the base resistance relative to a standard heterojunction transistor. In this reporting period, the device has been modeled analytically to verify performance potential and determine the required process parameters. Techniques for preparation of the metal grids have been developed, first with T-W, and later with pure W. Extensive experiments were conducted on epitaxial growth of GaAs and AlGaAs over the metal, and doping of GaAs and AlGaAs. Epitaxy is by metal-organic chemical vapor deposition, and Be and Zn have been used as the p-type dopants. A complete overhaul of the MOCVD reactor was completed in order to accommodate the Be dopant, as well as for incorporating very slow growth rates (50-100 A/min). To date, Be doping has been achieved to levels of 2 x 10 to the 19th power at /cu cm, with layer abruptnesses of about 100 A.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1988
- Accession Number
- ADA194763
Entities
People
- B.M. Paine
- H. Yamasaki
- M. J. Tejwani
- S. X. Bar
Organizations
- Hughes Aircraft Company