| 摘要 |
According to an example embodiment, a heterostructure bipolar transistor, HBT, includes shallow trench isolation, STI, structures around a buried collector drift region in contact with a buried collector. A gate stack including a gate oxide and a gate is deposited and etched to define a base window over the buried collector drift region and overlapping the STI structures. The etching process is continued to selectively etch the buried collector drift region between the STI structures to form a base well. SiGeC may be selectively deposited to form epitaxial silicon-germanium in the base well in contact with the buried collector drift region and poly silicon-germanium on the side walls of the base well and base window. Spacers are then formed as well as an emitter. |
