Current-voltage characteristics and X- ray diffraction study of Pd/Si1- xGex schottky contacts

The electrical characteristics of Pd/p-Si_1-xGe_x Schottky contacts have been investigated. The Schottky contacts were formed by depositing Pd metal on substrates at room temperature (RT = 300K) and at low temperature (LT = 77K). Post annealing was performed in nitrogen atmosphere at 450 and 550°C, respectively, to study the effect of silicide formation on contact characteristics. The current-voltage measurements showed that the barrier height, ϕ_B, decreased with the increase of the gemanium composition. The contact postannealed at 550°C showed a current transport mechanism obviously different from the as-deposited Schottky contacts. Nearly identical characteristics were observed for the low temperature deposited contacts and the room temperature deposited contacts with 550°C post-annealing. They both showed thermionic emission dominated transport mechanism. X-ray diffraction technique was used to characterize the effect of different temperature treatments on the crystal structure. The full width at half maximum of Si_1-xGe_x(400) phase decreased at low temperature deposited sample, while it increased at room temperature deposition.