Directed epitaxial heterojunction bipolar transistor
US9853136B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2014 |
| Grant date | Dec 26, 2017 |
| Priority date | — |
| Expiry date | Nov 8, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/406
Abstract
A directed epitaxial heterojunction bipolar transistor (HBT) structure is directly or indirectly formed on a GaAs substrate that is formed by a (100) face towards a (111)B face with an angle of inclination between 0.6° and 25°, and includes a sub-collector layer, a collector, a base layer, an emitter layer, an emitter cap layer and an ohmic contact layer, which are sequentially formed on the substrate. A tunnel collector layer formed by InGaP or InGaAsP is provided between the collector layer and the base layer. Since an epitaxial process is performed on the substrate from a (100) face towards a (111)B face with an angle of inclination between 0.6° and 25°, indium and gallium contained in InGaP or InGaAsP are affected by the ordering effect such that InGaP or InGaAsP used in the emitter layer and/or the tunnel collector layer has a higher electron affinity or a smaller bandgap.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.