COPPER AS AN ELECTRON TRAP IN GAAS0.6P0.4

An electron trap having an energy level of 0.14 eV from the conduction band edge was found in the bulk of copper-diffused VPE-grown n-GaAs0. 6P0.4 by conventional DLTS measurements and by pulse-duration dependen t capacitance amplitude measurements. The capture cross section at roo m temperature is about 1.0 x 10(-21) cm2 and has a weak temperature de pendence. These properties are attributed to a non-repulsive center ha ving a capturing mechanism which involves multiphonon emission process es with hardly any lattice relaxation. Evolution of the spatial distri butions of the traps with time under junction electric field were stud ied. The results suggest that the trap is positively charged and has a high diffusivity under electric field. The center can thus be identif ied as positively charged interstitial copper ion rather than some for m of copper complexes.