Molecular beam epitaxy Si/4H-SiC heterojunction diodes

The physical and electrical properties of silicon layers grown by molecular beam epitaxy (MBE) on commercial 4H-SiC substrates are reported. We investigate the effect of the Si doping type, Si doping concentration, Si temperature deposition and SiC surface cleaning procedure. Si/SiC monolithic integration of Si circuits with SiC power devices can be considered as an attractive proposition and has the potential to be applied to a broad range of applications. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to determine the Si crystal structure (cubic silicon) and morphology. I-V and C-V measurements are performed to evaluate the rectifying diode characteristics along with the Si/SiC built-in potential and energy band offsets. In the last section, we propose that our n-n Si/SiC heterojunction diode current characteristics can be explained by an isojunction drift-diffusion and thermoionic emission model where the effect of doping concentration of the silicon layer and its conduction band offset with SiC is analysed.