ALGAAS AND GAASP HIGH-POWER ULTRAFAST P+-N-N+ DIODES BASED ON HETEROJUNCTIONS AND A GRADED-GAP BASE

This paper presents a theoretical model of power p+-n-n+ diodes with a graded-gap base and either homojunctions (GB) or heterojunctions (HGB), and numerical calculations of static and dynamic characteristics of AlGaAs (GaAsP) based structures. It is shown that HGB diodes will exhibit characteristics and properties significantly better than those of simple homojunctions plus uniform base) GaAs and Si diodes. For example, the forward voltage drop in a high-voltage (W/L(p) = (13) high-frequency (t(rr) = 25 ns) HGB diode will be 50% and 300% smaller than the drop in, respectively, simple GaAs and Si diodes with the same W/L(p) and t(rr). Other significant projected improvements include operation up to 450-degrees-C, an order of magnitude reduction in the reverse current, and a 50% increase in the breakdown voltage.