Growth of Gallium Arsenide Using Ion Cluster Beam Technology.
Final rept. Sep 83-May 84,
EPI-TECH CORP PARADISE VALLEY AZ
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The growth of single crystal gallium arsenide GaAs epitaxial films on high resistivity GaAs substrates has been demonstrated. Films were grown at substrate temperatures from 600C down to 400C with thicknesses from 3000A to 5 micron. Growth rates were typically 150Aminute at all growth temperatures with thickness uniformity of or - 5 over the sample typical sample size 0.7in. X 0.7in.. The thickness was measured by a standard cleave and stain method. Single crystal behavior was shown using x-ray diffraction and SEM channeling patterns. Auger analysis was done on the films and showed characteristics comparable to those of the substrate. Hall data taken on the samples found the samples to be n-type, but with very low mobility. The low mobility is the result of defects grown into the structure because of high energy ions impinging on the surface. The energy of the ions was in the range of 100 to 1000 ev because of the small cluster size. The cluster had sizes of 10-50 atoms instead of the desired 500-2000 atomscluster. This smaller cluster is likely due to non-uniform heating of the crucibles by the e-beam filament. In addition, the diameterlength of the opening in the nozzle was 11. Recent work suggests a 110 ratio will allow more interactions and thus enhance the possibility of forming larger clusters. With larger clusters, lower energy per ion will be possible and the native defects will be reduced.
- Particle Accelerators
- Solid State Physics