Zinc doping of InP by metal organic vapour phase diffusion (MOVPD)

High p-doping of InP is desirable for buried heterostructure lasers and pho todiodes. The maximum hole concentration in zinc doped InP grown by MOVPE i s limited to 2 x 10(18) cm(-3). On the other hand, a sealed ampoule diffusi on process can be used but this suffers from poor reproducibility and surfa ce morphology. Diffusion of zinc in InP was carried out in a multi wafer MO VPE reactor with DEZn as a precursor. Diffusion temperature, DEZn concentra tion and diffusion time were optimised to obtain a high hole concentration. In situ annealing was used to activate the zinc. The maximum hole concentr ation obtained with zinc MOVPD is 8 x 10(18) cm(-3). A specular surface is achieved for all zinc concentrations up to 2 x 10(19) cm(-3). The zinc diff usion depth can be controlled reproducibly from 0.3 to over 3 mu m. Depth a nd doping uniformity over a two inch wafer is comparable to MOVPE growth. E xcellent results for InP/InGaAs photodiodes were obtained by local zinc MOV PD on a 2 in wafer. (C) 1998 Elsevier Science B.V. All rights reserved.