ULTRA-LOW-POWER AND HIGH-SPEED SIGE BASE BIPOLAR-TRANSISTORS FOR WIRELESS TELECOMMUNICATION SYSTEMS

Ultra-low-power and high-speed SiGe base bipolar transistors that can be used in RF sections of multi-GHz telecommunication systems have bee n developed. The SiGe base and a poly-Si/SiGe base-contact were formed by selective growth in a self-aligned manner. The transistors have a very small base collector capacitance (below 1 fF for an emitter area of 0.2 x 0.7 mu m) and exhibit a high maximum oscillation frequency (3 0-70 GHz) at low current (5-100 mu A). The power-delay product of an E CL ring oscillator is only 5.1 fJ/gate for a 250-mV voltage swing. The maximum toggle frequency of a one-eigth static divider is 4.7 GHz at a switching current of 68 mu A/FF.