INTERMIXING OF ION-IMPLANTED AlGaAs/GaAs SUPERLATTICES.

Cross-sectional Transmission Electron Microscopy, Sputter-Auger spectroscopy, and Raman spectroscopy have been used to study intermixing and residual damage in annealed ion-implanted Al//0//. //3Ga//0//. //7As/GaAs superlattices. Several implant species were studied (Se, Si, Mg, Be). Three different regions can be distinguished in the annealed ion-implanted superlattice samples. The topmost region contains a dense network of stacking faults and microtwins, residual damage from an implantation-amorphized region which has recrystallized during annealing. In the second region, which is relatively defect-free, either total, or at least appreciable intermixing of the GaAs and Al//0//. //3Ga//0//. //7As layers occurs. For fixed annealing conditions, the degree of intermixing varies with the mass of the implanted species. The third region contains many small dislocation loops which form by the agglomeration of point defects during implantation or the subsequent annealing process.