The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 1989
Filed:
Jul. 17, 1987
Anthony F Levi, Millburn, NJ (US);
American Telephone & Telegraph Company, AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
An improved compound semiconductor hot electron transistor (HET) having room temperature current gain .beta.>10 is disclosed. Disclosed are also means by which improved HET performance can be obtained. Among these means is choice of the base layer material such that the hot electrons injected into the base have k.sub.i,2 /k.sub.i,1 >0.2, where k.sub.i,1 and k.sub.i,2 are the components of the electron wave vector respectively normal and parallel to the emitter/base interface. A further means is choice of collector material such that the hot electron velocity component normal to the base/collector interface remains relatively unchanged upon passage of the hot electron through the base/collector interface. For instance, an appropriate superlattice in the collector region may be used to achieve such matching. Causing quantization of the ambient charge carrier states in the base can reduce hot electron scattering in the base. In bipolar HETs such scattering can also be reduced if the effective heavy hole mass in the base is much larger (e.g.,.times.10) than the effective electron mass in the forward direction. A strained base layer may be used to achieve this.