Study of process induced localized elevated oxygen concentration in strained boron doped sub-50 nm SiGeC base layers for high frequency npn HBTs

摘要

This work is believed to be the first report of localized elevated oxygen concentration (or pileup), which occurs with thermal anneals of strained, boron doped SiGeC layers. The thermally activated oxygen updiffusion is directly correlated to concentrations of germanium, carbon, and boron. A strong dependency on prebake temperature was also found. SIMS (secondary ion mass spectrometry) measurements were made to verify O, C, B, and Ge concentrations in SiGeC layers following low temp growth by LPCVD (low pressure chemical vapor deposition) and also following thermal anneal.