MISORIENTATION DEPENDENCE OF ZINC INCORPORATION IN GAAS

Doping studies of zinc have been carried out for metalorganic chemical vapour deposition (MOCVD) grown GaAs, with diethyl zinc as precursor. The zinc incorporation has been studied as a function of the zinc inp ut mole fraction, growth temperature and substrate misorientation. It is found that the zinc incorporation on (001) substrates misoriented t owards [01BAR1] and [011] directions showed a consistent and similar d ependence on the misorientation angle at various zinc input mole fract ions, with an observed minimum in the Zn-incorporation at 4-degrees of f. The observed temperature dependence leads to a apparent activation energy of -59 kcal/mol for zinc incorporation which is attributed to t he enthalpy involved in the formation of two bonds during the incorpor ation. The dependence on the misorientation angle is explained by comp etition between the influence of ''step trapping'' at lower misorienta tion (and higher step velocities) and the increase of available kinksi tes at higher misorientation angles.