# US 10,319,830 B2 · Heterojunction bipolar transistor power amplifier with backside thermal heatsink

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- Number: US 10,319,830 B2
- Document ID: US10319830B2
- Status: Granted
- Kind: B2
- Application number: 15/597,386
- Filed: 2017-05-17
- Published: 2018-07-26
- Granted: 2019-06-11
- Earliest claimed: 2017-01-24
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Bin Yang; Gengming Tao; Xia Li
- Web page: https://patentgrep.com/patent/US10319830B2

## CPC

- H10D 10/021: {of heterojunction BJTs [HBT]}
- H10D 10/821: {Vertical heterojunction BJTs}
- H10W 40/226: {characterised by projecting parts, e.g. fins to increase surface area (leadframes for cooling H10W70/461)}
- H10W 40/228: {the projecting parts being wire-shaped or pin-shaped}
- H10W 70/461: {specially adapted for cooling}
- H10D 62/137: {Collector regions of BJTs}
- H10D 62/824: comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions
- H10D 62/826: comprising only Group II-VI materials heterojunctions, e.g. CdTe/HgTe heterojunctions
- H10D 64/231: {Emitter or collector electrodes for bipolar transistors}
- H10W 74/00: Encapsulations, e.g. protective coatings
- H10W 90/766: {between a chip and a stacked lead frame, conducting package substrate or heat sink}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A heterojunction bipolar transistor may include an emitter, a base contacting the emitter, a collector contacting the base, a sub-collector contacting the collector, and an electrical isolation layer contacting the sub-collector. The heterojunction bipolar transistor may also include a backside heatsink thermally coupled to the sub-collector and the collector. The backside heatsink may be aligned with a central axis of the emitter and the base.

## Claims

### Claim 1

A heterojunction bipolar transistor, comprising:
an emitter;
a base contacting the emitter;
a collector contacting the base;
a sub-collector contacting the collector;
means for dissipating heat from the collector through the sub-collector; and
a thermally conductive etch stop layer lining the sub-collector and arranged between the means for dissipating heat and the sub-collector.

### Claim 2 (depends on 1)

The heterojunction bipolar transistor of claim 1, integrated into a chip of a wireless transceiver, the wireless transceiver incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer.

### Claim 3 (depends on 1)

The heterojunction bipolar transistor of claim 1, in which the means for dissipating heat directly contacts a backside of the thermally conductive etch stop layer and a front-side of the thermally conductive etch stop layer lines the sub-collector.

### Claim 4 (depends on 1)

The heterojunction bipolar transistor of claim 1, in which the sub-collector is comprised of a III-V compound semiconductor material or a II-VI compound semiconductor material.

### Claim 5 (depends on 1)

The heterojunction bipolar transistor of claim 1, in which the thermally conductive etch stop layer comprises aluminum arsenide (AlAs).

### Claim 6

A heterojunction bipolar transistor, comprising:
an emitter;
a base contacting the emitter;
a collector contacting the base;
a sub-collector contacting the collector;
a backside thermal via thermally coupled to the collector through the sub-collector, in which the backside thermal via is substantially aligned with the emitter and the base; and
a thermally conductive etch stop layer lining the sub-collector and arranged between the backside thermal via and the sub-collector.

### Claim 7 (depends on 6)

The heterojunction bipolar transistor of claim 6, integrated into a chip of a power amplifier incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer.

### Claim 8 (depends on 6)

The heterojunction bipolar transistor of claim 6, in which the backside thermal via directly contacts a backside of the thermally conductive etch stop layer and a front-side of the thermally conductive etch stop layer lines the sub-collector.

### Claim 9 (depends on 6)

The heterojunction bipolar transistor of claim 6 in which the sub-collector is comprised of a III-V compound semiconductor material or a II-VI compound semiconductor material.

### Claim 10 (depends on 6)

The heterojunction bipolar transistor of claim 6, in which the thermally conductive etch stop layer comprises aluminum arsenide (AlAs).