Heterojunction bipolar transistor
US5523594A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 5, 1995 |
| Grant date | Jun 4, 1996 |
| Priority date | — |
| Expiry date | Jun 5, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D10/821
Abstract
An AlGaAs/GaAs heterojunction bipolar transistor in which a base doping concentration is set to be as very high as 5.times.10.sup.19 cm.sup.-3 or more to cause a band gap narrowing effect and to reduce a band gap difference by an amount corresponding to the band gap narrowing effect, an Al composition ratio, i.e., x in an Al.sub.x Ga.sub.1-x As material of an emitter layer is set to be less than 0.25, whereby an emitter resistance can be made small, an operating speed can be made fast and a current gain can be made high. Preferably, the base doping concentration is set to be 1.2.times.10.sup.20 cm.sup.-3 or more so that the operation speed can be made remarkably fast.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.