T. Egilsson

The material quality of CVD-grown SiC using different carbon precursors

Abstract We report an investigation where nine different hydrocarbons have been used as carbon precursor in the growth of 4H and 6H silicon carbide (SiC) epitaxial layers. For the various growths the C/Si ratio was varied from 2 to 6, the temperature in the range 1550–1600°C, and the growth rate was about 3–4.6 μm/h. All hydrocarbons, except methane, could be used for growth of high crystal quality epitaxial layers at low C/Si ratio and low growth rate (3 μm/h) as confirmed by the smooth morphology, and by low-temperature photoluminescence showing strong free exciton and narrow well-resolved nitrogen-bound exciton lines. Hydrogen-related lines could be observed in the spectra of epitaxial layers grown with C-precursors which have double and triple bonds in the molecule. The unintentional incorporation of p-type dopants, such as, aluminium and boron impurities is proposed to correlate to the surface roughness. Propane gave the most stable growth of the hydrocarbons as C-precursor at higher growth rate.

Zeeman spectroscopy of the D1 bound exciton in 3C–, and 4H–SiC

We have studied the D1 bound exciton (BE) in 3C-SiC (cubic) and 4H-SiC (hexagonal) by means of Zeeman spectroscopy. We show that the D-1-BE can be described by an electron-hole pair consisting of a ...

Excitation spectra of nitrogen bound excitons in 4H- and 6H-SiC

We report photoluminescence excitation spectra of the nitrogen (N) donor bound excitons (BE) in 4H- and 6H-SiC. The spectra reveal several excited states of the N-BEs. An attempt is made in the article to classify the N-BE states according to a simple shell model.

Photoluminescence excitation spectra of the free exciton emission in 6H–SiC

Abstract We have applied photoluminescence excitation spectroscopy of the free-exciton related emission in 6H–SiC for studying the absorption edge. Detailed comparison with the conventional techniques, absorption measurements and wavelength modulated spectroscopy, is carried out, and our results are compared with those obtained from these techniques. A qualitative model of the absorption mechanism is proposed in order to understand the appearance of peaks in the PLE spectra.