Rutherford backscatter measurements on tellurium and cadmium implanted gallium arsenide.

16 cm-2) of cadmium and telluriumcan be implanted without forming amorphous lattice disorder by heating the gallium arsenide during implantation to relatively low temperatures (~ 200°C) at which no appreciable dissociation of the gallium arsenide or broadening of the implanted profiles by diffusion occurs. Atom site location measurements have shown that a large fraction of a tellurium dose implanted at 180°C is located on or near lattice sites but that in the case of cadmium the fraction depends on the implanted dose. Channelled backscatter measurements have shown that there is residual disorder or lattice strain in gallium arsenide implanted at elevated temperatures. The extent of this disorder has been shown to depend on the implanted dose and implantation temperature. The channeling effect has been used to measure annealing of the disorder. It has been concluded from this work that for high dose implantations of cadmium and tellurium, it is more advantageous to implant at 180°C than at room temperature. To achieve efficient doping, however, it could be necessary to anneal the residual lattice disorder. Pyrolitieally deposited silicon dioxide is not a suitable encapsulation for this purpose