A novel npn InGaAs bipolar transistor with a wide gap cadmium oxide (CdO) emitter

A CdO film was deposited on an InGaAs pn junction to form an npn bipolar transistor, which can be used also as a phototransistor. The high conductivity of CdO ( sigma =5*103/ Omega cm) reduces the emitter contact resistance and what a refractive index of n equivalent to 2.2 at 1.15 mu m wavelength the transparent film can serve as an antireflective window. The processing of the transistor is described. A current gain of hfe=10 (VCE=3V, Ic=1mA) and an emitter-collector breakdown voltage of VCEO=6V were obtained.