Device technology for high-yield and high-performance InP/InGaAs DHBTs

This paper describes InP double-heterojunction bipolar transistors (DHBTs) technology for 40 Gbit/s IC applications. Our DHBTs feature a carbon-doped InGaAs base and an InGaAs/InGaAsP/InP step-graded collector with its conduction-band potential profile properly controlled by a doping dipole. The fabricated transistors have current gain of 30, breakdown voltage, BVCEO, of over 8 V, and ideal collector-current turn-on behaviour up to 1 mA/mum(2). Sixty-eight transistors on a 3-inch substrate exhibit average current gain cutoff frequency,f(t), of 131 GHz and average maximum oscillation frequency,f(max), of 191 GHz with standard deviations of 1.5% and 7.9%, respectively, at current density, J(C), of 0.5 mA/mum(2) and collector voltage, V-CE, of 1.2 V.