InGaAs---GaAs pseudomorphic heterostructure transistors prepared by MOVPE

In this paper, we will demonstrate two new InGaAs-GaAs pseudomorphic heterostructure transistors prepared by MOVPE technology, i.e. InGaAs-GaAs graded-concentration doping-channel MIS-like field effect transistors (FET) and heterostructure-emitter and heterostructure-base (InGaAs-GaAs) transistors (HEHBT). For the doping-channel MIS-like FET, the graded In_0.15Ga_0.85As doping-channel structure is employed as the active channel. For a 0.8 × 100 μm² gate device, a breakdown voltage of 15 V, a maximum transconductance of 200 mS/mm, and a maximum drain saturation current of 735 mA/mm are obtained. For the HEHBT, the confinement effect for holes is enhanced owing to the presence of GaAs/InGaAs/GaAs quantum wells. Thus, the emitter injection efficiency is increased and a high current gain can be obtained. Also, due to the lower surface recombination velocity of InGaAs base layers, the potential spike of the emitter-base (E-B) junction can be reduced significantly. This can provide a lower collector-emitter offset voltage. For an emitter area of 4.9 × 10⁻⁵ cm², the common emitter current gain of 120 and the collector-emitter offset voltage of 100 mV are obtained.