Surface Preparation Study in GaAs HBT Process

Y. Recsei, C. Luo, S. Tiku, P. Zampardi

Skyworks Solutions, 2427 W. Hillcrest Drive, Newbury Park, CA 91320 catherine.luo@skyworksinc.com (805) 480-4553

Keywords: Surface Preparation, BC Diode Turn on Voltage, HBT Reliability

Abstract:

We report the results of an experiment to investigate the impact of surface cleaning methods on the HBT base-collector turn-on voltage and transistor reliability. This experiment indicates that NH4OH based solution is an appropriate surface preparation method for processing GaAs based HBTs. Deviation from this cleaning procedure (no clean, DI water clean or acetic acid clean) degrades the device performance and reliability. This is consistent with previous finding in literature that NH4OH based solution produces a cleaner, more stoichiometric GaAs surface resulting in better device performance.

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