Interface Structure of P-Type GaP/Au/Au-Zn

Studies on the microstructure of the GaP/Au/Au-Zn system were carried out with an electron microscope and X-ray energy spectrometer. It was shown that an AuGa layer was formed at the interface between GaP and the Au/Au-Zn layer, and that the AuGa reaction layer contained Zn atoms. It is considered that the AuGa layer may contribute to the mechanical strength of the deposit layer for wire bonding and reliable ohmic contact for a P-type GaP. The Au underlayer seems to promote the formation of the AuGa layer, which starts forming at 490°C.