In order to prevent carriers in multi-layer heterostructures from being redistributed, a new method for open-tube Zn diffusion, using an In-Zn alloy as the source and a polycrystalline InP cover to limit surface thermo-damage at temperature as low as 500C, was developed. It was found that the diffusion rate was proportional to the square of the P content. When using proper masking, the ratio of the lateral width to the diffusion depth was about 0.6.

W.Li, H.Pan: Journal of the Electrochemical Society, 1987, 134[9], 2329-32