Reliability investigation of implanted microwave InGaP/GaAs HBTs

In this paper, wt report the fabrication and characterisation of C-doped In GaP/GnAs microwave HBTs using a planar self-aligned technology based on O+/ H+ or O+/He+ implant isolation schemes. We observed current gain variations with emitter/base geometries in the H+ implanted HBTs while no such variat ion was observed in the He+ implanted transistors. This latter phenomenon i s characterised by a cut rent gain increase in the smaller, device and this was attributed to a decrease of the hole concentration in the base, caused by the formation of C-H complexes in the C-doped GaAs base region. We ther efore recommend the use of O+/He+ implant scheme for the fabrication of rel iable high performance C-doped base HBTs. (C) 2001 Elsevier Science B.V. Al l rights reserved.