Ultra high speed heterojunction bipolar transistor having a cantilevered base
US6680494B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 2001 |
| Grant date | Jan 20, 2004 |
| Priority date | — |
| Expiry date | Mar 2, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/824
Abstract
Reduction in the base to collector capacitance of a heterojunction bipolar transistor, and, improved high frequency performance is achieved using existing materials and processes by undercutting the collector (5) under the base (7) along two parallel sides of the base mesa (7—FIG. 4), and providing a sloped collector edge (5—FIG. 6) along the remaining two parallel sides of the base. The foregoing is accomplished by selective etching and with the four sides of the mesa regions oriented as a non-rectangular parallelogram (7, 9—FIG. 4) in which one pair of sides is in parallel with one of the said [0 0 1] and [0 0 {overscore (1)}] planes of the crystalline structure and the other pair of sides in parallel with one of the [0 1 1] and [0 {overscore (1)} {overscore (1)}] planes of the crystalline structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.