Multi-step rapid thermal annealing of boron and indium implanted Hg1−xCdxTe
In this work, we are reporting the use of a two-step rapid thermal annealing (RTA) process (250°C, 100s+340°C, 30s) for the annealing of Hg1−xCdxTe (MCT) implanted layers over p-type (x=0.22) substrates. We report a high value of electrical activation (70%) of the indium implants after this short RTA treatment in inert Ar atmosphere. The need of two RTA steps in the annealing recipe is shown, and so the role played by each of them: the first step annihilates the implantation damage, while the second one produces the impurity electrical activation. However, for the boron case, no electrical activity was found after several annealing processes, behaving as an inert species for the case of this bulk MCT material. We also point out the change on the substrate electrical characteristics induced by the thermal treatments, and report the convenience of a subsequent low temperature furnace annealing (200°C, 72 h) to reduce back the bulk carrier concentration to values low enough to achieve an n+-p IR detector structure.