Phosphorus doping of polycrystalline CdTe by diffusion

Phosphorus diffusion in single crystal and polycrystalline CdTe material is explored using various methods. Dynamic secondary ion mass spectroscopy (SIMS) is used to determine 1D P diffusion profiles. A 2D diffusion model is used to determine the expected cross-sectional distribution of P in CdTe after diffusion anneals. Time of flight SIMS and cross-sectional cathodoluminescence corroborates expected P distributions. Devices fabricated with diffused P exhibit hole concentrations up to low 10¹⁵ cm^-3, however a subsequent activation anneal enabled hole concentrations greater than 10¹⁶ cm^-3. CdCl₂ treatments and Cu based contacts were also explored in conjunction with the P doping process.