Characterization of paramagnetic defect centers in three polytypes of dry heat treated, oxidized SiC

Abstract

This work describes the characterization of defect centers in 3C–SiC, 4H–SiC, and 6H–SiC. The different SiC crystal structures are examined with electron paramagnetic resonance after thermal oxidation, and after dry (<1 ppm H2O) N2 or O2 heat treatment. The centers are described by g values that range from 2.0025 to 2.0029, which are typical of C dangling bonds. Because the centers are activated in ambients that eliminate H2O and are passivated in ambients that contain H2O, it is suggested that the centers are C dangling bonds created during the dry heat treatment when hydrogen or a hydrogenous species releases from C bonds. The activation characteristics for the centers is the same for both 6H and 3C polytypes; however, centers in the 6H–SiC samples are passivated at lower temperatures than the centers in the 3C–SiC samples. The passivation behavior is attributed to differences in the hydrogen diffusion rates in these materials rather than significant differences in the chemistry of the centers. Etching studies conducted with hydrofluoric acid indicate that the centers are not located in the SiO2, but are located in the SiC at a distance of, at most, 200 nm from the SiO2/SiC interface.

Identification of the Carbon Dangling Bond Center at the4H−SiC/SiO2Cantin1, Bardeleben2, Shishkin3 et al. 2004Phys. Rev. Lett.922691View full textAdd to dashboardCite

“…In spite of various attempts, no oxidation related defect has been observed in 3C-, 4H-, and 6H-SiC. Only a post oxidation high temperature annealing induced isotropic defect, attributed to carbon dangling bonds in the oxide, has been reported [13]. These negative results seem to contradict the electrical measurements.…”

“…The EPR measurements P H Y S I C A L R E V I E W L E T T E R S were performed at 35 and 9 GHz in the 4 to 300 K temperature range. The angular variation of the spectra has been observed for a rotation of the magnetic field in the (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and (1-100) planes. Because of the only partial resolution of the observed multiline spectrum, a computer-assisted decomposition has been performed.…”

Alternative techniques to reduce interface traps in n‐type 4H‐SiC MOS capacitors

“…Angle-resolved X-ray photoelectron spectroscopy [6], atomic force microscopy [7], and combined transmission electron microscopy/energy loss spectroscopy [8] investigations revealed carbon particles at SiC/SiO 2 -interfaces. Electron spin resonance (ESR) investigations [9] discovered paramagnetic centers, which were related to dangling bonds of C atoms in a surrounding of amorphous carbon. Internal electron photoemission (IPE) spectra show significant similarities between spectra taken either on electron states in the SiC bandgap of SiC/SiO 2 -structures or taken at interfaces of hydrogenated amorphous carbon (a-C:H)/SiO 2 structures [10].…”

Effects of high-temperature annealing on defects and impurities in As-grown semi-insulating 4H SiC

“…1a may be separated into a broad, ϳ15-G wide, isotropic line centered at g ϭ 2.004 and a 0.7-G wide, anisotropic line at g ϭ 2.0033. The broad line has been attributed to surface damage due to polishing and cutting of the samples 8,9 and the narrow line to a carbon vacancy related defect (V C ). 4 The magnetic field location of the latter is indicated by the dotted line in Fig.…”