A CRYO-BiCMOS technology with Si/SiGe heterojunction bipolar transistors

A high-performance liquid-nitrogen temperature BiCMOS (CRYO-BiCMOS) technology with Si/SiGe heterojunction bipolar transistors (HBTs) is presented. The newly developed HBT, which has an n/sup +/-polysilicon/n-type Si epitaxial layer emitter structure on a p-type SiGe base layer, shows a high current gain of 50 at liquid nitrogen temperature. Under the conditions of 3.3 V and 83 K, the driving capability of CRYO-BiCMOS gates is two times larger than that of the CRYO-CMOS gate. At 3.3 V and a load capacitance of 1 pF, the gate delay of CRYO-BiCMOS gate with pull-up HBT is 480 ps. The CRYO-BiCMOS with Si/SiGe HBTs presented is very promising for the future progress of BiCMOS LSIs. >