Freescale Semiconductor, Inc. Tempe Fab 2100 E. Elliot Road, Tempe, AZ, 85284 terry.daly@freescale.com; jason.fender@freescale.com; agni.mitra@freescale.com; matt.parker@freescale.com; darrell.hill@freescale.com; r10895@freescale.com
Keywords: HBT, base ideality, metal liftoff, surface cleans
Abstract
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.