Microstructure of Cr-B Ohmic and Rectifying Contacts on (0001) 6H Sic

Abstract

6H-SiC is a wide band-gap semiconductor. In recent years, a variety of high-power, -temperature, -speed and opto-electronic devices have been produced in 6H-SiC films. The future development of SiC device technology depends on the ability to form good ohmic and Schottky contacts. Plots of the current-voltage (I-V) characteristics of Cr-B contacts on (0001) 6H-SiC revealed that they became the most ohmic-like after annealing at 1000 °C for 240 sec. and rectifying after annealing for 300 sec, therefore TEM analysis of the microstructures of as-deposited and annealed Cr-B films should help in understanding what causes both the ohmic-like and rectifying behaviors.In this research, CrxBy film was deposited on vicinal (0001) 6H-SiC substrates by electron beam evaporation at room temperature. The intended phase was CrB2. Fig.l shows the microstructure of the as-deposited specimen. 6H-SiC appears to be a perfect crystal, but the Cr-B film had columnar polycrystalline microstructure.