HOLE TRAP GENERATION BY THERMAL-TREATMENT OF NITROGEN-DOPED P-TYPE ZNSE ON GAAS CHARACTERIZED BY DEEP-LEVEL TRANSIENT SPECTROSCOPY

The influence of a thermal treatment on hole trap generation in nitrog en doped ZnSe on GaAs was investigated by means of deep level transien t spectroscopy. The samples were grown by molecular beam epitaxy (MBE) on highly zinc doped p-type GaAs(001) substrates. p-type doping of th e ZnSe epilayer was performed by applying a rf nitrogen plasma during MBE growth. In order to carry out electrical measurements Schottky con tacts were prepared by evaporating gold (Au) on top of the ZnSe. A dom inant hole trap with a thermal activation energy of about 0.65 eV, sho wing a strong temperature dependence of the hole capture cross section , was determined. It was found that the concentration of this trap inc reases by more than one order of magnitude after an annealing of the A u/ZnSe/GaAs samples at 550 K and that it is responsible for hole compe nsation effects. (C) 1997 American Institute of Physics.