Heterojunction bipolar transistor fabrication using Si1−xGex selective epitaxial growth by gas source silicon molecular beam epitaxy

Abstract

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−xGex by gas source Si-MBE, B-doped Si1−xGex selective epitaxial growth was found to be possible. This B-doped Si1−xGex selective epitaxial growth was applied to Si1−xGex/Si heterojunction diode and Si1−xGex 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.

Optical Transitions in a Self-Assembled Ge Quantum Dot/Si Superlattice Measured by Photoreflectance Spectroscopy

“…1) There are several applications of SiGe in optical devices, like photodetector, terahertz laser, 2) high electron mobility transistor (HEMT), and heterojunction bipolar transistor (HBT). 3) Most recently, the quantum dot infrared photodetector (QDIP) has attracted a lot of attentions because it possesses merits of high quantum efficiency, 4) normal incident, low dark current as compared to the quantum well infrared photodetector (QWIP). 5,6) Many experimental techniques, such as Raman, 7) Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL), 8) had been used to characterize the optical and electronic properties of the Ge quantum dot/Si superlattice.…”