Interfacial reaction and electrical property of Ge/Ni/ZnSe for blue laser diode
Interfacial reaction and electrical property of the Ge/Ni/ZnSe have been investigated as a fundamental study to develop ohmic contacts to p-ZnSe, using x-ray diffraction, Auger electron spectroscopy, cross-sectional transmission electron microscopy, and capacitance-voltage measurement. Ni/ZnSe, Ni/Ge systems have been also studied for comparison with the Ge/Ni/p-ZnSe system and the electrical property could be related to the interfacial reaction. After annealing at 170°C, Ni3Se2 and NiGe were formed at Ni/ZnSe and Ge/Ni interface, respectively. The increase of annealing temperature resulted in the decomposition of Ni3Se2 through the reaction with Ge. The change of the Schottky barrier height strongly depended on the annealing temperature. According to the result of Ni/ZnSe interface reaction, Ni3Se2 in the Ni/ZnSe interface lowered the Schottky barrier height. At higher annealing temperature, the Schottky barrier height increased and it was mainly due to the thermal decomposition of ZnSe.