New SiGe bipolar transistors and p-i-n diodes for power switching

We have first fabricated bipolar transistors and p-i-n diodes for power swi tching by using SiGe. The misfit dislocation with the Ge addition in the fi lm allows the reduction of minority carrier lifetime in the film. If the Ge concentration in the SiGe layer is chosen in the range below 10% to avoid the excessive misfit dislocation, the breakdown characteristics of pn-junct ion at the SiGe/Si heterojunction are not deteriorated. When SiGe is used a t the base layer in the npn(-)n(+) bipolar transistors, the fast switching time of similar to 20 ns is possible in the 280V-20A class bipolar transist ors, while the low on-voltage drop of 0.34 V is achieved at the collector c urrent density of 113 A/cm(2). Moreover, if SiGe is applied to the p-anode in the thin -p/n(-)n(+)-diodes, the recovery time can be lowered more than 50% compared with the Si diodes with the same structure.