Compensation of shallow impurities in oxygen-doped metalorganic vapor phase epitaxy grown GaAs

Abstract

Intentional oxygen incorporation, using diethyl aluminum ethoxide [(C2H5)2AlOC2H5] during metalorganic vapor phase epitaxy GaAs was found to compensate C and Zn shallow acceptors as well as Si and Se shallow donors, due to the oxygen-related multiple deep levels within the GaAs band gap. Deep level transient spectroscopy (DLTS) was used to characterize the energy levels associated with these oxygen deep centers. The total measured trap concentration from DLTS can account for the observed compensation in n-type GaAs:O. The total trap concentration in p-type GaAs:O, however, was found to be lower than the observed compensation by a factor of ∼100. These oxygen deep centers exhibit multiple electronic states which have been associated with the local number of Al nearest neighbors and the microscopic structure of the defect. The concentration and nature of these deep levels were not influenced by the chemical identity of the shallow dopants. © 1996 American Institute of Physics.