Method of fabricating a bipolar transistor
AssigneeInnovative Technology Licensing, LLC
InventorsRichard L. Pierson JR., James Chingwei Li, Berinder P.S. Brar, John A. Higgins
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Abstract
A thin InGaAs contact layer is provided for the collector of a heterojunction bipolar transistor (HBT) above an InP sub-collector. The contact layer provides a low resistance contact mechanism and a high thermal conductivity path for removing device heat though the sub-collector, and also serves as an etch stop to protect the sub-collector during device fabrication. A portion of the sub-collector lateral to the remainder of the HBT is rendered electrically insulative, preferably by an ion implant, to provide electrical isolation for the device and improve its planarity by avoiding etching through the sub-collector.
Claims32
A heterojunction bipolar transistor (HBT), comprising:
- successive emitter, base and collector layers,
- an InP sub-collector layer, and
- a thermally conductive InGaAs contact layer between said collector and sub-collector layers.
A double heterojunction bipolar transistor (DHBT), comprising;
- an InP or InAlAs emitter,
- an InGaAs base,
- an InP collector,
- an InP sub-collector, and
- an InGaAs contact layer between said collector and sub-collector which establishes, together with the sub-collector, a low resistance contact to the collector, said contact layer being thin enough to provide a substantially higher thermal conduction path between said collector and sub-collector than would bulk InGaAs.
A heterojunction bipolar transistor (HBT), comprising:
- successive emitter, base and collector layers, and
- an InP sub-collector layer having an electrically insulative portion which electrically isolates the HBT.
A method of fabricating a heterojunction bipolar transistor, comprising:
- forming in succession an InP sub-collector layer, a thin electrically conductive InGaAs contact layer, and collector, base and emitter layers on a substrate, and
- etching said collector, base and emitter layers to a desired shape, using said contact layer as an etch stop to protect said sub-collector layer when the 10 collector layer is etched.
A method of electrically isolating a bipolar transistor, comprising:
- forming said transistor with an InP sub-collector, and
- rendering a portion of said sub-collector electrically insulative to electrically isolate the transistor.
Dependencies are inferred from the claim text.