The role of elevated temperatures in the implantation of GaAs

The improvement in conductivity resulting from implanting n-type dopants into GaAs at elevated temperatures has been investigated. Measurement of the rate of introducing compensating defects at elevated temperatures shows only marginal reduction from the room temperature rate. The avoidance of lattice disorder buildup also has minimal effect on carrier recovery and the amount of residual compensation after annealing. It appears that compensation cannot account for the improved conductivity of heated implants and that alternatively a substantial fraction of the room temperature introduced ions, even with annealing, must fail to become substitutional in the first instance. For sulfur, the same temperature dependence consistent with the established behavior of selenium and tellurium is obtained. An increase in conductivity by a factor of 2·5 occurs ? 150°C to give up to 40 per cent utilization from 10¹⁴ S⁺ cm^?2 implants.