Study of deep level defects in doped and semi-insulating n-6H-SiC epilayers grown by sublimation method

Deep level transient spectroscopy (DLTS) is employed to study deep level defects in n-6H-SiC (silicon carbide) epilayers grown by the sublimation method. To study the deep level defects in n-6H-SiC, we used as-grown, nitrogen doped and nitrogen-boron co-doped samples represented as ELS-1, ELS-11 and ELS-131 having net (ND–NA) ∼2.0×1012cm−3, 2×1016cm−3 and 9×1015cm3, respectively. The DLTS measurements performed on ELS-1 and ELS-11 samples revealed three electron trap defects (A, B and C) having activation energies Ec – 0.39eV, Ec – 0.67eV and Ec – 0.91eV, respectively. While DLTS spectra due to sample ELS-131 displayed only A level. This observation indicates that levels B and C in ELS-131 are compensated by boron and/or nitrogen–boron complex. A comparison with the published data revealed A, B and C to be E1/E2, Z1/Z2 and R levels, respectively.