Thermal stability of deep levels between room temperature and 1500 °C in as-grown 3C-SiC

Abstract

We report on the thermal stability of deep levels detected in as-grown bulk 3C-SiC. The investigation was performed by Fourier-transform deep level transient spectroscopy and an isochronal annealing series was carried out in the 100-1500°C temperature range. We found three traps located between 0.14-0.50 eV below the conduction band edge minimum ͑E C ͒. The shallower trap anneals out at temperatures below 1200°C while the others display a high thermal stability up to at least 1500°C. The nature of the former trap is discussed in detail on the basis of its annealing behavior and previous theoretical data found in the literature.

Kinetics of the 3C-6H polytypic transition in 3C-SiC single crystals: A diffuse X-ray scattering study

“…1,17 The undulant (001) Si substrates exhibit trenches running parallel to the [1][2][3][4][5][6][7][8][9][10] direction which allows to significantly reduce the density of the defects which are usually encountered in the heteroepitaxial growth of 3C-SiC on (001) Si, namely anti-phase boundaries (APBs) and SFs lying in the {111} planes. It must however be mentioned that this growth process produces highly anisotropic single crystals.…”

“…First, because defect annihilation takes place progressively during growth, the region close to the SiC/Si interface (hereinafter designated as the "lower side") exhibits a high density of APBs, SFs, and twin boundaries, 18 whereas the region close to the SiC surface (hereinafter designated as the "upper side") exhibits a far better crystalline quality. 19 Second, the trenches being parallel to the [1][2][3][4][5][6][7][8][9][10] direction, the annihilation mechanism is only efficient for those SFs lying in the (111) and (-1-11) planes, whereas those lying in the (-111) and (1-11) planes are not affected. Consequently, on the upper side of the crystals, the SF density is higher along the [1-10] direction (6.4 Â 10 3 cm À1 ) than along the [110] direction (1.4 Â 10 3 cm À1 ).…”

“…Consequently, on the upper side of the crystals, the SF density is higher along the [1-10] direction (6.4 Â 10 3 cm À1 ) than along the [110] direction (1.4 Â 10 3 cm À1 ). 20 The influence of this anisotropic crystalline quality (i.e., upper side vs. lower side and [110] vs. [1][2][3][4][5][6][7][8][9][10]) on the polytypic transition will be discussed in Sec. III B.…”

“…This direction contains all information regarding the stacking sequence of close-packed structures and is commonly used to monitor polytypic transitions. 25 The intensity distribution along the [10L] h direction is extracted from the RSM for each sample and for each orientation of the sample (i.e., with either the [110] or the [1][2][3][4][5][6][7][8][9][10] parallel to the incident beam and with either the upper or the lower side exposed to the incident beam). These [10L] h -scans are then simulated with a numerical model in order to extract the polytype volume fraction and the level of transformation.…”

“…11 On the contrary, studies dealing with the transformation of 3C-SiC single crystals are extremely scarce and, to the best of our knowledge, the question of the transformation kinetics has not been addressed to date. This lack of experimental data regarding the 3C-6H polytypic transition in single crystals is due (1) to the above-mentioned difficulties to grow 3C-SiC single crystals and (2) to the lack of quantitative characterization tools that would allow to obtain quantitative information concerning the transformation (transformation level and polytype volume fraction). Qualitative information, for instance regarding the transformation mechanism or the nature of the polytypes that are formed, have been obtained using TEM, 12 Raman scattering, 13,14 or x-ray rotation photography.…”