Improvement of Base Ideality through Improved Surface Cleans

Terry Daly, Jason Fender, Agni Mitra, Matt Parker, Darrell Hill, and Adolfo Reyes

Freescale Semiconductor, Inc. Tempe Fab 2100 E. Elliot Road, Tempe, AZ, 85284;;;;;

Keywords: HBT, base ideality, metal liftoff, surface cleans


For both commercial and industrial applications, HBT intrinsic reliability requires that performance does not degrade with time. Long-term reliability has been associated with low-voltage base current [1, 2], of which one source is base ideality. This paper explores factors affecting surface cleanliness and their influence on base ideality, including base metal evaporation and post-metal liftoff cleans.

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