Abstract
A method for making a heterojunction bipolar transistor includes the following steps: forming a heterojunction bipolar transistor by depositing, on a substrate, subcollector, collector, base, and emitter regions of semiconductor material; the step of depositing the subcollector region including depositing a material composition transition from a relatively larger bandgap material nearer the substrate to a relatively smaller bandgap material adjacent the collector; and the step of depositing the collector region including depositing a material composition transition from a relatively smaller bandgap material adjacent the subcollector to a relatively larger bandgap material adjacent the base.
| Original language | English (US) |
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| U.S. patent number | 7297589 |
| Filing date | 4/8/05 |
| State | Published - Nov 20 2007 |