The reliable and well controlled electrical contacts are needed for the successful operation of almost all solid state semiconductor devices. Metal-semiconductor (MS) structures play a vital role in devices based on the III-V compound semiconductors in the form of Schottky barrier diodes or ohmic contacts. Being a III-V compound semiconductor, indium phosphide (InP) based MS structures have found potential applications in microwave and optical devices such as field effect transistors, solar cells, light emitters, and detectors. The fabrication of high quality Schottky barrier is an essential prerequisite for the development of these devices. Schottky contacts play an important role in controlling the electrical performance of semiconductor devices. The Schottky barrier height (SBH) is very sensitive to the thermal treatment of the MS interfaces. Hence, the fabrication of thermally stable Schottky contacts with high barrier height and low-reverse leakage current still up till now represents a challenge.