Properties of thermally annealed undoped and sulphur doped InP wafers

Different thermal treatments on bulk undoped and S doped InP were carried out. The ambient atmosphere, temperature, heating, and cooling conditions were varied to study the influence of each individual parameter on sample characteristics. It is apparent that annealing in a P atmosphere is preferable for electrical and crystallographic homogeneity. The physical and structural properties of InP annealed under vacuum suggest that indiffusion of In takes place. The In at the surface is available because of the rapid P evaporation during the sample heating. Depending on the cooling conditions, the diffused In atoms can be gettered by dislocations and cause micro defects. A hypothesis of Inp antisite formation (and corresponding suppression of P vacancies) is also proposed to justify the Hall, photoluminescence, and positron lifetime data.