Heterojunction bipolar transistor
US5698871A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1995 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | Oct 13, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D10/821
Abstract
A heterojunction bipolar transistor includes a compound semiconductor substrate, a collector layer disposed on the compound semiconductor substrate, a base layer disposed on the collector layer, the base layer being a semiconductor having a band gap energy and including an internal base region and an external base region, and an emitter layer disposed on the base layer and being a semiconductor having a band gap energy larger than the band gap energy of the semiconductor of the base layer. The base layer is larger in area than the emitter layer by the external base region. The external base region is sandwiched by insulating films at the external base region. Therefore, without ion-implantation to make the resistance of the collector layer below the external base region higher, i.e., without increasing the base resistance, the base-collector capacitance is reduced, resulting in an HBT having an improved high frequency gain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.