Heterojunction bipolar transistor
US10629712B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 2018 |
| Grant date | Apr 21, 2020 |
| Priority date | — |
| Expiry date | Jul 3, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/824
Abstract
A collector layer of an HBT includes a high-concentration collector layer and a low-concentration collector layer thereon. The low-concentration collector layer includes a graded collector layer in which the energy band gap varies to narrow with increasing distance from the base layer. The electron affinity of the semiconductor material for the base layer is greater than that of the semiconductor material for the graded collector layer at the point of the largest energy band gap by about 0.15 eV or less. The electron velocity in the graded collector layer peaks at a certain electric field strength. In the graded collector layer, the strength of the quasi-electric field, an electric field that acts on electrons as a result of the varying energy band gap, is between about 0.3 times and about 1.8 times the peak electric field strength, the electric field strength at which the electron velocity peaks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.