Comparison of crystal orientation dependence for the solid phase epitaxial process in ion implanted Si and GaAs

Solid phase epitaxial (SPE) regrowth is studied using the time-resolved reflectivity technique in ion implanted semiconductors with different substrate orientations. In silicon evidence for a planar (100) growth front and a roughening (111) growth front is given. In GaAs the crystal/amorphous interface roughness is shown to increase with recrystallized depths in the (100) and (111) direction, the latter having the most degraded interfacial structure. The (110) substrate orientation in GaAs is shown to have a more stable interface during growth. The growth rate and activation energy of the SPE process is conserved in all GaAs orientations. While regrowth in silicon agrees qualitatively with the general crystal growth approach to growth on flat faces and kinked faces, the departure of GaAs from this scheme is explained by chemical disorder. Results support the hypothesis that the crystal/amorphous GaAs interface is rough and microfaceted in the (111) directions.