@article{aca2fab2773c46e0ac332c242c8a20e7,
title = "Electron capture and emission properties of interface states in thermally oxidized and NO-annealed SiO2/4H-SiC",
abstract = "Postoxidation annealing in nitric oxide (NO) results in a significant reduction of electronic states at SiO2 /4H-SiC interfaces. Measurements of electron trapping dynamics at interface states in both thermally oxidized and NO annealed SiO2 /4H-SiC interfaces were performed using constant-capacitance deep level transient spectroscopy (CCDLTS) and double-CCDLTS. We show that the interface state density in as-oxidized samples consists of overlapping distributions of electron traps that have distinctly different capture cross sections. The dominant trap distributions, centered at Ec -0.24 eV with ∼7× 10-19 cm2, and at Ec -0.46 eV with ∼4× 10-17 cm2 are passivated by NO annealing. The remaining interface states all have capture cross sections in the range 10-19 - 10-21 cm2.",
author = "Chen, {X. D.} and S. Dhar and T. Isaacs-Smith and Williams, {J. R.} and Feldman, {L. C.} and Mooney, {P. M.}",
note = "Funding Information: We are grateful to W. Woods in the SFU School of Engineering Sciences for assistance with wire bonding. This work was supported by the National Sciences and Engineering Research Council of Canada, the Canadian Foundation for Innovation, the British Columbia Knowledge Development Fund, the U.S. Army Research Office, the U.S. Army TACOM, and the Defense Advanced Research Projects Agency. FIG. 1. C − V data at 1 MHz for (a) AO and (b) NO SiO 2 / 4 H-SiC MOS capacitors. FIG. 2. CCDLTS spectra for the AO sample measured with (a) varying filling pulse duration at filling pulse voltage 13 V and (b) varying filling pulse voltage at 20 ms duration. The rate window is 8.6 ms and the constant capacitance is 42 pF. FIG. 3. CCDLTS spectra for the NO sample measured with (a) varying filling pulse duration at filling pulse voltage 5 V and (b) with varying filling pulse voltage at 20 ms duration. The rate window is 8.6 ms and the constant capacitance is 18 pF. FIG. 4. CCDLTS spectra measured for (a) AO and (b) NO SiO 2 / 4 H-SiC . The filling pulse duration is 20 ms to achieve saturation of the signal and the rate window is 8.6 ms. The constant capacitance is 42 pF and the filling pulse voltage is 13 V for the AO and 18 pF and 5 V for the NO sample. FIG. 5. Double-CCDLTS scans for (a) the AO sample and (b) the NO sample at the filling voltages indicated. Scans for the latter are offset vertically. The constant capacitance was 42 pF for the AO sample and 18 pF for the NO sample. The filling pulse duration is 20 ms, and the rate window is 8.6 ms. FIG. 6. Arrhenius plots: (a) representative data from double-CCDLTS scans for the AO sample with filling pulse voltages 7.0/6.0, 10.0/9.0, and 13.0/12.0 V at constant capacitance 42 pF and (b) double-CCDLTS data for the NO sample with pulse voltages 3.5/3.0 and 5.0/4.5 V at constant capacitance 18 pF and CCDLTS data (open symbols) with filling pulse voltage 5 V. FIG. 7. Capture cross section and emission activation energy determined from double-CCDLTS (solid symbols) and CCDLTS (open symbols) measurements for the AO (squares) and the NO (triangles) samples. The uncertainty in the activation energy is 0.02 eV and it is an order of magnitude in the capture cross section. FIG. 8. Distribution of SiO 2 / 4 H-SiC interface states obtained from CCDLTS and high-low C − V measurements on AO and NO samples. ",
year = "2008",
doi = "10.1063/1.2837028",
language = "English",
volume = "103",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "3",
}