Calculations predict the carbon antisite to be the most abundant intrinsic defect in silicon carbide in a wide range of doping. The isolated carbon antisite is, however, optically and electronically inactive, therefore, difficult to observe by usual experimental techniques. However, C Si can trap mobile impurities forming electrically active complexes. We will show by ab initio supercell calculations that the hydrogen interstitial is trapped by the carbon antisite forming an electrically active defect which might be detectable by different spectroscopic techniques. The key to activate C Si by hydrogen is to introduce sufficient amount of hydrogen in the SiC samples and to avoid formation of vacancies or boron-hydrogen complexes. We have found that the concentration of C Si+H complex is above 10 13 cm -3 in highly doped p-type chemical vapor deposited (CVD) layers as well as in highly doped p-type and n-type SiC samples annealed in high temperature high pressure (HTHP) H 2 gas. The concentration of C Si+H complex can be enhanced in Al-doped CVD and HTHP SiC samples by applying the appropriate post-annealing temperature. The C Si+H complex might be also detected in Al-doped SiC samples irradiated at room temperature by low energy H 2 + ions.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Jan 1 2005|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics