SiGe HBT technology: A new contender for Si-based RF and microwave circuit applications

The silicon-germanium heterojunction bipolar transistor (SiGe HBT) is the first practical bandgap-engineered device to be realized in silicon. SiGe HBT technology combines transistor performance competitive with III-V technologies with the processing maturity, integration levels, yield, and hence, cost commonly associated with conventional Si fabrication. Inn the ten-and-one-half Sears since the first demonstration of a functional transistor, SiGe HBT technology has emerged from the research laboratory, entered manufacturing on 200-mm wafers, and is poised tea enter the commercial RF and microwave market. State-of-the-art SiGe HBT's can deliver: 1) f(T) in excess of 50 GHz; 2) f(max) in excess of 70 GHz; 3) minimum noise figure below 0.7 dB at 2.0 GHz; 4) 1/f noise cooler frequencies below 500 Hz; 5) cryogenic operation; 6) excellent radiation hardness; 7) competitive power amplifiers; and 8) reliability comparable to Si. A host of record-setting digital, analog, RF, and microwave circuits have been demonstrated in the past several years using SiGe HBT's, and recent work on passives and transmission Lines on Si suggest a migratory path to Si-based monolithic microwave integrated circuits (MMIC's) is possible. The combination of SiGe HBT's with advanced Si CMOS to form an SiGe BICMOS technology represents a unique opportunity for Si-based RF system-on-a-chip solutions. This paper reviews state-of-the-art SiGe HBT technology and assesses its potential for current and future RF and microwave systems.