InP HBT Transferred to Higher Thermal Conductivity Substrate

Abstract

We report the first demonstration of an InP double heterojunction bipolar transistor (HBT) transferred to a higher thermal conductivity substrate. This process allows lithographic access to both the frontside and backside of the device to minimize parasitic capacitances while transfer to a SiC substrate should reduce junction temperature by 42%, allowing for higher current density operation. The 0.20 × 3 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> emitter-area HBT has peak common-emitter current gain β = 22 and breakdown V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BR</sub> , <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CEO</sub> >; 4 V. No electrical degradation from the transferred-substrate process is observed. RF measurements show device peak <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">τ</sub> = 397 GHz, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ≥ 400 GHz, and maximum available gain (MAG) at 100 GHz is 15.3 dB.