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US 7,804,109 B2Granted
Heterojunction bipolar transistor and method for manufacturing the same, and power amplifier using the same
AssigneeRenesas Electronics Corporation
InventorsIsao Ohbu, Chushiro Kusano, Yasunari Umemoto, Atsushi Kurokawa
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Abstract
A heterojunction bipolar transistor with InGaP as the emitter layer and capable of both reliable electrical conduction and thermal stability wherein a GaAs layer is inserted between the InGaP emitter layer and AlGaAs ballast resistance layer, to prevent holes reverse-injected from the base layer from diffusing and reaching the AlGaAs ballast resistance layer.
Claims4
A heterojunction bipolar transistor having a sequentially formed structure comprising:
- an InGaP emitter layer;
- a GaAs base layer lying below the InGaP emitter layer and forming a heterojunction together with the InGaP emitter layer;
- an AlGaAs ballast resistance layer lying above the InGaP emitter layer;
- and
- a low-doped GaAs layer lying between the InGaP emitter layer and the AlGaAs ballast resistance layer,
- wherein the donor concentration of said low-doped GaAs layer is less than that of the AlGaAs ballast resistance layer.
3 more elements
Dependencies are inferred from the claim text.