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US 6,806,513 B2Granted
Heterojunction bipolar transistor having wide bandgap material in collector
AssigneeEiC Corporation
InventorsHin Fai Chau, Clarence John Dunnrowicz, Yan Chen, Chien Ping Lee
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Abstract
The safe operating area (SOA) in a heterojunction bipolar transistor is improved by inserting a material between the collector and subcollector of the transistor with the insertion layer being a material having a wider energy bandgap than the material of the collector. The insertion layer increases the breakdown field at the collector-subcollector junction and thereby increases the Kirk effect induced breakdown voltage.
Claims27
A heterojunction bipolar transistor (HBT) comprising
- a) an emitter region of one conductivity type,
- b) a base region of opposite conductivity type abutting the emitter region, material in the emitter region having an energy bandgap that is wider than the energy bandgap of material in the base region.
- c) a collector region of the one conductivity type abutting the base region, material in the collector region being the same as the material in the base region
- d) a subcollector region of the one conductivity type and of higher doping concentration than the collector region, and
- e) an insertion layer of the one conductivity type between and abutting the collector region and the subcollector region and having a lower doping concentration than the subcollector region, material of the insertion layer having an energy bandgap that is wider than the energy bandgap of material in the collector region and the insertion layer is thinner than the collector region.
2 more elements
A heterojunction bipolar transistor (HBT) comprising
- a) an emitter region of one conductivity type,
- b) a base region of opposite conductivity type abutting the emitter region, material in the emitter region having an energy bandgap that is wider than the energy bandgap of material in the base region,
- c) a collector region of the one conductivity type abutting the base region, material in the collector region being the same as the material in the base region,
- d) a subcollector region of the one conductivity type and of higher doping concentration than the collector region, and
- e) an insertion layer of the one conductivity type comprising at least first and second layers with the first layer abutting the collector region and the second layer abutting the subcollector region, the doping of the first layer being less than the doping of the second layer and the doping of the subcollector, the first layer being thinner than the collector region.
2 more elements
Dependencies are inferred from the claim text.