DEGRADATION OF ZNSE ZNTE MULTIQUANTUM-WELL CONTACTS TO P-ZNSE/

The work presented in this paper studied the degradation of ZnTe/ZnSe multiquantum well contacts to p-ZnSe under high current loading(1000 t o 1500 A/cm(2)). During degradation, localized heating (up to 200 degr ees C > the bulk substrate and heat sink) was observed to occur at the point were electrical power was supplied. Auger data from degraded sa mples indicated that due to the localized heating, Zn and Te from the ZnTe layers and Zn from the ZnSe layer diffused through the Au metalli zation to the samples surface. In addition, thermal stress from the lo calized heating generated micro-cracks in the ZnSe which acted as high diffusivity paths for impurities. Rectangular defects were also found to form in the degraded region. These defects were oriented to the mi cro-cracks and had similar geometries as dislocation patches (dark lin e defects) which have been reported to form in the quantum well region of degraded ZnSe based laser devices. The similarities between the re ctangular defects and dark line defects suggest the formation of simil ar dislocation patches in the quantum well region of the multiquantum well contacts.