Soichi Kimura

Monolithic integration of an InGaAsP/InP laser diode with heterojunction bipolar transistors

A monolithic integration of an InGaAsP laser diode together with current supplying circuit on a single InP substrate has been achieved. Heterojunction bipolar transistors (HBT’s) have been constructed utilizing the burying epitaxial layers of the buried heterostructure laser diode. The laser has been successfully modulated up to 1.6 GHz through the HBT’s driving circuit with sinusoidal electrical signal.

InGaAsP/InP heterojunction bipolar transistor grown by MOVPE

Abstract An InGaAsP( λ g = 1.2 μ m)/InP DHBT for use wavelength (1.3—1.55 μm) OEICs has been successfully fabricated, on a semi-insulating Fe-doped InP substrate, by a low pressure MOVPE method. Current-voltage characteristics of the emitter-base and base-collector junctions exhibit ideality factors of 1.81 and 1.34, respectively, and almost the same built-in voltages of 0.9 V, indicating that the p-n junctions are formed at the heterointerfaces of p-InGaAsP and n-InP, which is consistent with a SIMS analysis of the impurity depth profile. The common emitter characteristics of a typical DHBT show no offset voltage, small Farly effect, and a higher breakdown voltage of more than 10 V. The current gain ( h FE ) is about 160 at a collector current ( I c ) of 10 mA. The h FE has a small dependence on I c in the range from 1 μA to 10 mA ( h FE ∼ I 0.25 c ). The dependence of the cutoff frequency ( f T ) on the I c shows that the best f T is 3.6 GHz at I c = 20 mA.