Physical properties of sulfur double donors in 4H-SiC introduced by ion implantation

The activation ratio and the ionization energy (Δ E ) of sulfur (S) atoms implanted in n-type 4H-SiC were investigated. It was revealed that implanted sulfur atoms show almost no diffusion during activation annealing at 1750 °C and the electrical activation ratio determined by capacitance–voltage measurement is nearly 100%. The net donor concentration showed good agreement with twice the S atom density, which means that a S atom works as a double donor. Δ E was estimated to be in the range of 340–520 meV for four donor levels by Hall effect measurement and admittance spectroscopy.