Development of High Breakdown Voltage InGaP/GaAs DHBTs

Jiang Li1, Cristian Cismaru1, Pete Zampardi1, Andy Wu1, Eugene Babcock1 Mike Sun1, Kevin Stevens2, and Ravi Ramanathan1

1Skyworks Solutions, Inc., 2427 West Hillcrest Drive, Newbury Park, CA 91320 2Kopin Corporation, 695 Myles Standish Blvd., Taunton, MA 02780 Email: Jiang.li@skyworksinc.com, Phone: (805) 4804442

Keywords: InGaP, GaAs, High breakdown, DHBT

Abstract

In this paper, we report the development of a high breakdown voltage InGaP/GaAs HBT process for lowtomid power and highvoltage power amplifier operation. To achieve the highbreakdown InGaP HBT, two different collector designs and collectoretch processes were investigated. The first device process approach uses a thick GaAs collector with low ndoping. The process challenges and considerations of this long collector approach are briefly discussed. An alternative approach uses wide band gap InGaP material as part of the collector design. High breakdown voltage can be obtained from both material design approaches. However, to fully leverage the existing process modules of our high volume HBT production line and allow the reuse of our current HBT design rules and libraries, our high voltage HBT (HVHBT) development efforts focus on HBTs with InGaP in the collector (either composite collector, CCHBT, or double heterojunctions, DHBTs). Using a slightly modified process, InGaP DHBT devices have been demonstrated with BVceo and BVcbo values of 40 V and 56 V, respectively. A cut off frequency, ft, of 40 GHz has also been obtained at a current density of Jc=0.3 mA/�m2 by using this process. Preliminary circuit level performance results are also presented and discussed.

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