Electrical properties of strained nano-thin 3C-SiC/Si heterostructures

The effects of strain on the conduction mechanism in heterostructures consisting of strained nano-thin 3C-SiC films on Si are reported. These films exhibit significantly different electrical behaviours than the bulk material. Strained nano-thin 3C-SiC films were grown on n-type Si substrates by gas source molecular beam epitaxy. Reflection high-energy electron diffraction patterns show that these films are about 3% strained relative to the SiC lattice constant. In order to investigate the electrical properties of thin film structures, Al, Cr and Pt contacts to a nano-thin film 3C-SiC were deposited and characterized. The I-V measurements of the strained nano-thin films demonstrate back-to-back Schottky diode characteristics and the band offsets due to the biaxial tensile strain introduced within the 3C-SiC films were calculated and simulated. Based on the experimental and simulation results, an empirical model for the current transport in the heterostructures based on strained nano-thin films has been proposed. It was found that due to the band alignment of this structure, current is constrained at the surface which allows use of nano-thin films as surface sensors.