Fabrication and characterization of InP:Zn layers for optoelectronic and microwave devices

The outcomes of experimental study of InP:Zn layers, obtained by Zn diffusion in an InP unprotected surface in an open system, are presented. The influence of the thermal annealing in nitrogen and hydrogen atmospheres, carried out before the Zn diffusion, on the InP parameters was studied. It is shown that under annealing of InP in nitrogen atmosphere, the nitrogen saturated near the surface layer which precludes phosphorus vaporization and reduces generation of recombination centers in p-n junction n-region formation. It has been found that annealing of InP substrates in nitrogen atmosphere before Zn diffusion results in an increase of electron diffusion length, degree of Zn electrical activity, and effective life time of minority charge carriers in the p-n junction n-region. The application indicated that annealing in the fabrication technology of InP/InGaAs p-i-n photodiodes has allowed a dark current density of 4.2×10^-8 A/cm² at the reverse bias voltage of 5 V.