GaInP/GaAs tunnel collector HBTs: base-collector barrier height analysis

Tunnel collector HBTs employ a thin layer of GaInP between the GaAs base and collector regions, in order to suppress hole injection when the base-collector junction is forward biased. Devices with a low offset voltage of 30 mV, and low knee voltage of /spl sim/0.3 V, while still maintaining high current gain (170), and good RF performance with f/sub T/=54 GHz and f/sub MAX/=68 GHz have been demonstrated. The devices exhibit increased output conductance as compared to conventional GaInP/GaAs SHBTs, due to a residual barrier at the base-collector junction. This paper presents an experimental method for the determination of such barriers, by analyzing the collector current as a function of applied base-collector voltage, V/sub CB/.