Silicon germanium virtual substrate growth and silicon(1-y)germanium(y)/silicon(1-x)germanium(x)/silicon(1-y)germanium(y) HBTs for millimeter-wave applications

Recently, relaxed SiGe virtual substrate on Si wafer attracted a lot of interests due to potential applications in devices like strain-Si HEMT, MOSFET, etc and the ability for integration with CMOS. In this work, two methods for the growth of SiGe virtual substrate are studied: compliant substrate and low temperature (LT) Si buffer.; Borosilicate glass compliant substrate is fabricated by boron and oxygen implantation into SOI wafer and high temperature annealing. The 20% BSG substrate is demonstrated to be a very effective compliant substrate to grow high quality SiGe film with 0.3 Ge content.; The growth of SiGe films on LT Si buffer has been studied in detail. Crystal quality of the SiGe film is improved by optimizing growth conditions of the LT Si buffer layer. The strain compliant effect of the LT Si buffer is demonstrated experimentally.; Si_1−yGe_y/Si_1−xGe_x/Si _1−yGe_y HBT is proposed basing on the SiGe virtual substrate. DC and RF performances are simulated for different material and device structures by using mathematical method and Silvaco physical software. A series of Si _1−yGe_y/Si_1−xGe_x/Si _1−yGe_y HBTs with different Ge contents are grown, fabricated and characterized. It is proposed that integration of SiGe/Ge/SiGe HBT and photodiode is a promising candidate for optical transceiver used in 1.55μ m fiber communication.