Dislocation density after S-diffusion into p-type InP substrates

Abstract

The increase in dislocation density at the surface of Zn-doped and Cd-doped p-type InP wafers as a result of heat-treatment and closed-ampoule sulfur diffusion was studied. This research was prompted by the observation of consistently lower efficiencies for solar cells made on Zn-doped as compared to Cd-doped InP substrates of nearly identical dopings and etch pit densities, under identical diffusion conditions. For an 11.83% (AM0, 25 degrees C) solar cell made from diffused Zn-doped substrate, the surface dislocation density was about 2*10/sup 7/ cm/sup -2/, whereas for 14.35% (AM0, 25 degrees C) solar cells made from diffused Cd-doped substrate, the surface dislocation density was about 8*10/sup 5/ cm/sup -2/.<>