CDTE ROTATION GROWTH ON SILICON SUBSTRATES BY METALLOORGANIC CHEMICAL VAPOR-DEPOSITION

We observed a 30-degrees in-plane rotation slip for (111) CdTe epilayers grown on (111) Si substrates by metallo-organic chemical vapour deposition when we increased the group VI to II ratio. We define this effect as rotation growth. This rotation alignment reduces the lattice mismatch between CdTe and silicon from 19% to 3.4%, thus promising better crystallinity. When the group VI to II ratio is increased, the full width at half-maximum of the X-ray rocking curve is decreased from over 1000'' to 400'' for an epilayer 1 mum thick. The rotation growth mechanism was examined by Auger electron spectroscopy and results show that the tellurium atoms are adsorbed to the silicon surface more readily than are cadmium atoms. We also found that the (111) Si substrate had to be n-misoriented toward the [101BAR] direction to suppress twinning in CdTe rotation growth.