Preparation of homogeneous InP substrates by VGF-growth and wafer annealing

We have analyzed the microscopic and macroscopic uniformity of as-grown and annealed low Fe-doped InP-wafers grown by different methods (LEC, vertical gradient freeze). Though the annealing is advantageous with respect to the levelling of striations, additional non-uniformity on the microscopic scale is created. The origin of these spots of enhanced photoluminescence might be related to a gettering of Fe at dislocations, which in consequence leaves a vicinity with a reduced Fe-concentration.