Effects of deposition temperature on Mo/SiC Schottky contacts

We report on the results of our investigation of the effect of deposition temperature on molybdenum (Mo) used as Schottky contacts to fabricate silicon carbide (SiC) Schottky barrier diodes. The contacts were deposited using magnetron sputtering on n-type 4H-SiC at temperatures ranging from 25 to 900 °C. The fabricated diodes were characterized by current–voltage, current–voltage–temperature, and capacitance–voltage measurements. The diodes showed average Schottky barrier heights that decreased from 1.54 to 1.00 eV with increasing deposition temperature of the contacts. The average values of the ideality factors similarly decreased from 1.21 to 1.06 with increasing deposition temperature. However, the diodes with contacts deposited at 400–900 °C nearly maintained a constant ideality factor value of 1.06. The x-ray diffraction analysis indicated that silicides were formed at the interface for contacts deposited at or above 400 °C. The improved properties of the diodes with contacts deposited at higher temperatures are correlated with the formation of the interfacial alloys possessing improved electrical properties. This work demonstrates that high temperature deposition is another method for optimizing the properties of Mo contacts for the fabrication of 4H-SiC Schottky diodes for electronic applications in high power and high temperature environments.