A 45 GHz strained-layer SiGe heterojunction bipolar transister fabricated with low temperature epitaxy

Strained-layer Si-SiGe heterojunction bipolar transistors with f/sub t/ as high as 45 GHz are reported. The device structure incorporates a 65 nm SiGe graded base, with a peak Ge concentration of 11%, grown by UHV/CVD (ultrahigh vacuum/chemical vapor deposition) low-temperature epitaxy. The devices show a 10* collector current enhancement and a 30% reduction in base transit time to 2.6 ps.<
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