Patent attributes
The present invention relates to a high performance heterojunction bipolar transistor (HBT) having a base region with a SiGe-containing layer therein. The SiGe-containing layer is not more than about 100 nm thick and has a predetermined critical germanium content. The SiGe-containing layer further has an average germanium content of not less than about 80% of the predetermined critical germanium content. The present invention also relates to a method for enhancing carrier mobility in a HBT having a SiGe-containing base layer, by uniformly increasing germanium content in the base layer so that the average germanium content therein is not less than 80% of a critical germanium content, which is calculated based on the thickness of the base layer, provided that the base layer is not more than 100 nm thick.
