TEMPERATURE STABILITY OF COBALT SCHOTTKY CONTACTS ON N-TYPE AND P-TYPE 6H SILICON-CARBIDE

Rectifying Schottky contacts have been manufactured on n- and p-type 6H silicon carbide using e-beam evaporation of cobalt. Heat treatments in the 300 to 1100 degrees C temperature range have been made to study the feasibility of high temperature contacts in this material system. Rutherford backscattering spectrometry and X-ray diffraction have revealed the formation of different cobalt silicides (Co2Si, CoSi, and CoSi2) at higher temperatures than for the Co/Si system. No evidence of silicidation was found below 600 degrees C and SEM micrographs revealed carbon agglomerates at the surface after silicidation. Electrical properties have been examined using I-V and C-V measurements, and the barrier heights of cobalt and Co2Si were evaluated. The contacts displayed excellent forward I-V characteristics with good linearity over 3-6 decades and were rectifying even after heat treatments al 800 degrees C.