Heterojunction bipolar transistor power amplifier with backside thermal heatsink

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.

What is claimed is: 
     
         1 . 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 heatsink thermally coupled to the sub-collector and the collector, in which the backside heatsink is substantially aligned with the emitter and the base; and   a backside ground via in electrical contact with the emitter.   
     
     
         2 . The heterojunction bipolar transistor of  claim 1 , in which the backside heatsink comprises a backside thermal via thermally coupled to the collector through the sub-collector. 
     
     
         3 . The heterojunction bipolar transistor of  claim 1 , further comprising a thermally conductive etch stop layer lining the sub-collector and arranged between the backside heatsink and the sub-collector. 
     
     
         4 . The heterojunction bipolar transistor of  claim 3 , in which the thermally conductive etch stop layer comprises aluminum arsenide (AlAs). 
     
     
         5 . The heterojunction bipolar transistor of  claim 3 , in which the thermally conductive etch stop layer comprises a thermally conductive layer, an etch stop layer, and an electrical insulator layer. 
     
     
         6 . The heterojunction bipolar transistor of  claim 3 , in which the backside heatsink is arranged to directly contact a backside of the thermally conductive etch stop layer and a front-side of the thermally conductive etch stop layer is arranged to line the sub-collector. 
     
     
         7 . 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. 
     
     
         8 . The heterojunction bipolar transistor of  claim 1 , 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. 
     
     
         9 . A heterojunction bipolar transistor-based power amplifier, 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 backside ground via in electrical contact with the emitter.   
     
     
         10 . The heterojunction bipolar transistor-based power amplifier of  claim 9 , further comprising a thermally conductive etch stop layer lining the sub-collector and arranged between the means for dissipating heat and the sub-collector. 
     
     
         11 . The heterojunction bipolar transistor-based power amplifier of  claim 10 , in which the thermally conductive etch stop layer comprises aluminum arsenide (AlAs). 
     
     
         12 . The heterojunction bipolar transistor-based power amplifier of  claim 10 , 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 is arranged to line the sub-collector. 
     
     
         13 . The heterojunction bipolar transistor-based power amplifier of  claim 9 , in which the sub-collector is comprised of a III-V compound semiconductor material or a II-VI compound semiconductor material. 
     
     
         14 . The heterojunction bipolar transistor-based power amplifier of  claim 9 , 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.