Indium phosphide-based heterojunction bipolar transistor technology for high-speed devices and circuits

The theoretical predictions for the performance of Heterojunction Bipolar Transistors (HBTs) have been largely based on models devised for silicon bipolar junction transistors (BJT). A careful inspection of the DC forward and reverse injection properties of HBTs has revealed that they are not reciprocal because of the heterojunction. The RF characteristics derived from an advanced network model indicated that {dollar}fsb{lcub}t{rcub}{dollar} and {dollar}fsb{lcub}max{rcub}{dollar} must be redefined since {dollar}hsb{lcub}21{rcub}{dollar} and U can no longer be considered single pole functions.; A variety of InP-based HBTs have been fabricated and characterized. The layer structures were grown by conventional molecular beam epitaxy (MBE) and by chemical beam epitaxy (CBE). A totally self-aligned base and emitter metal process was developed to characterize their DC and RF performances.; The CBE grown structures included InAlAs/InGaAs and InP/InGaAs single HBTs and InAlAs/InGaAs/InGaAsP double HBTs. The various structures showed comparable current gains {dollar}(betaapprox 100){dollar} but the different injecting and collecting junctions resulted in variations in turn-on voltages, ideality factors and offset voltages. Because of the large bandgap InGaAsP collector in the double HBT, its breakdown voltage (8V) is significantly larger than that of the single HBTs (2.5V). The microwave performance of all these HBTs is dominated by parasitics. The low doping efficiency of the CBE significantly increases the base resistance and the emitter access resistance.; The MBE grown HBT was a conventional InAlAs/InGaAs HBT with very heavily doped contact layers. The DC measurements showed lower current gain {dollar}(betaapprox 60){dollar} due to high base doping but demonstrated excellent Gummel and breakdown characteristics. Microwave measurements yielded an {dollar}fsb{lcub}t{rcub}{dollar} and {dollar}fsb{lcub}max{rcub}{dollar} of 65 and 78 GHz, respectively.; Cryogenic DC measurements were performed to study the injection and recombination mechanisms at the base-emitter junction. At low temperatures, tunneling injection and bulk base recombination dominate while at room temperature themionic emission and other recombination processes are activated. Microwave measurements at various temperature revealed that both {dollar}fsb{lcub}t{rcub}{dollar} and {dollar}fsb{lcub}max{rcub}{dollar} improve as the temperature is lowered.; The measured RF parameters of the MBE InAlAs/InGaAs HBT were used to design oscillators, amplifiers and photoreceivers. The oscillators operated at 7 and 14 GHz with output powers of 4 and 2 mW. The transimpedance amplifiers demonstrated a bandwidth of 17 GHz with a transimpedance of 40 {dollar}dBOmega{dollar}. The photoreceivers showed an optical bandwidth of 7 GHz and clearly open eye diagrams at 3 Gbits/s.