HETEROJUNCTION BIPOLAR-TRANSISTOR FABRICATION USING SI1-XGEX SELECTIVE EPITAXIAL-GROWTH BY GAS SOURCE SILICON MOLECULAR-BEAM EPITAXY

B doping in Si1-xGex was successfully achieved using HBO2 cell in gas source Si molecular beam epitaxy (Si-MBE). Combining this B doping method and selective epitaxial growth of Si1-xGe x by gas source Si-MBE, B-doped Si1-xGex selective epitaxial growth was found to be possible. This B-doped Si 1-xGex selective epitaxial growth was applied to Si 1-xGex/Si heterojunction diode and Si1-xGe x base heterojunction bipolar transistor (HBT) fabrications. The Si1-xGex base HBT (x=0.16, 0.22, 0.31) showed higher hFE in as-grown condition than that for a homojunction transistor. The band-gap difference between the Si1-xGex base and the Si emitter was estimated by the temperature dependence of the collector current ratio between the HBT and the homojunction transistor.