Non-Graded Base Si/Ge Heterojunction Transistor

Abstract

Innovation of Heterojunction Bipolar Transistor (HBT) technology is a major game changer in wireless communication, power amplifiers and other major fields of electronics. HBTs play a vital role in extending the advantages of silicon bipolar transistors to significantly higher levels. Research on HBT is focused on reducing cost and improving reliability.  These transistors have a wide range of applications namely, digital-to-analog converters, logarithmic amplifiers, RF chip sets for CDMA wireless communication systems, and power amplifiers for cellular communications. Our study focuses on utilizing the high mobility of pure Ge instead of often-used graded Ge base. Non-grtaded Ge base enhanses carrier transport which in turn increases the gain and cut-off frequency of the HBT. We have developed a high frequency, high current gain, high power gain and less noisy heterojunction bipolar transistor operating above 100GHz frequency. Lattice mismatch at emitter and collector junctions is compensated by inserting SiGe buffer layers. ATLAS TCAD - SILVACO software is used for modelling of this novel device.