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, Ni₃S₂ 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.