ABSTRACT Dc/ac transport characteristic of PECVD grown hydrogenated amorphous silicon carbide (a-SiCx:H) thin film was investigated in MIS (metal/insulator/semiconductor) structure by dc current/voltage (I/V) at different temperature (T), ac admittance vs. temperature at constant gate bias voltages and deep level transient spectroscopy (DLTS), respectively. According to I-V-T analysis, two main regimes exhibited. At low electric field, apparent Ohm’s law dominated with Arrhenius type thermal activation energy (EA) around 0.4 eV in both forward and reverse directions. At high field, on the contrary, space charge limited (SCL) current mechanism was eventual. The current transport mechanisms and its temperature/frequency dependence were interpreted by a thermally activated hopping processes across the localized states within a-SiCx:H thin film since 0.4 eV as EA was not high enough for intrinsic band conduction. Instead, transport of charge carriers took place in two steps; first a carrier is thermally excited to an empty energy level from an occupied state then multi-step tunnelling or hopping starts over. Therefore, the two steps mechanisms manifested as single activation energy, differing only through capture cross sections. In turn, two steps in capacitance together with conductance peaks in C-(G)-T while convoluted DLTS signal associated with such events in the measurements.
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nullO. Özdemir, K. Bozkurt and K. Kutlu, "Investigation of Electrical Transport in PECVD Grown a-SiCx:H Thin Film," Materials Sciences and Applications, Vol. 2 No. 8, 2011, pp. 993-999. doi: 10.4236/msa.2011.28134.
 J. Kanicki, “Amorphous and Microcrystalline Semiconductor Devices,” Materials and Device Physics, Vol. 2, Artech House, London, 1992.
 M. Vetter, C. Voz, R. Ferre, I. Mart?′n, A. Orpella, J. Puigdollers, J. Andreu and R. Alcubilla, “Electronic Properties of Intrinsic and Doped Amorphous Silicon Carbide Films,” Thin Solid Films, Vol. 511-512, 26 July 2006, pp. 290-294.
 S. Ogawa, M. Okabe, Y. Ikeda, T. Itoh, N. Yoshida and S. Nonomura, “Applications of Microcrystalline Hydrogenated Cubic Silicon Carbide for Amorphous Silicon Thin Film Solar Cells,” Thin Solid Films, Vol. 516, No. 5, 2008, pp. 740-742 doi.10.1016/j.tsf.2007.06.047
 S. J. Lee, S. H. Kim, D. W. Kim, K. H. Kim, B. K. Kim and J. Jang, “Effect of Hydrogen Plasma Passivation on Performance of HIT Solar Cells,” Solar Energy Materials & Solar Cells, Vol. 95, No. 1, January 2011, pp. 81-83.
 M. Vetter, I. Mart?′n, R. Ferre, M. Gar?′n and R. Alcubilla, “Crystalline Silicon Surface Passivation by Amo- rphous Silicon Carbide Films,” Solar Energy Materials & Solar Cells, Vol. 91, No. 2-3, 23 January 2007, pp. 174-179. doi.10.1016/j.solmat.2006.08.004
 Z. Hu, X. B. Liao, H. W. Diao, Y. Cai, S. B. Zhang, E. Fortunato and R. Martins, “Hydrogenated P-type Nan- ocrystalline Silicon in Amorphous Silicon Solar Cells,” Journal of Non-Crystalline Solids, Vol. 352, No. 9-20, 15 June 2006, pp. 1900-1903.
 S. Y. Myong, S. S. Kim and K. S. Lim, “Improvement of Pin-type Amorphous Silicon Solar Cell Performance by Employing Double Silicon-carbide Player Structure,” Journal of Applied Physics, Vol. 95, No. 3, 1 February 2004, pp. 1525-1530. doi.10.1063/1.1639140
 R. Ferre, I. Martín, M. Vetter, M. Garín and R. Alcubilla, “Effect of Amorphous Silicon Carbide Layer Thickness on the Passivation Quality of Crystalline Silicon Surface,” Applied Physics Letters, Vol. 87, No. 20, November 2005, pp. 109-202. doi.10.1063/1.2130530
 H. Fujiwara and M. Kondo, “Effects of A-Si:H Layer Thicknesses on the Performance of A-Si:H/c-Si Heterojunction Solar Cells,” Journal of Applied Physics, Vol. 101, No. 5, 2007, pp. 054516-054525.
 H. Fujiwara and M. Kondo, “Impact of Epitaxial Growth at the Heterointerface of A-Si:H/c-Si Solar Cells,” Applied Physics Letters, Vol. 90, No. 1, January 2007, pp. 013503-013506. doi.10.1063/1.2426900
 K. Sel, B. Akao?lu, ?. Atilgan and B. Katircio?lu, “Effects of Tail States on the Conduction Mechanisms in Silicon Carbide Thin Films with High Carbon Content,” Solid-State Electronics, Vol. 57, No. 1, March 2011, pp 1-8. doi.10.1016/j.sse.2010.12.010
 M. Grünewald, P. Thomas and D. Würtz,” Simple Calculation of the Hopping Conductivity for an Exponential Band Tail,” Physics States Solid (B), Vol. 94, No.1, July 79, pp. K1-K4.
 S. Nespurer, O. Zmeskal and F. Schauer, “An Ohmic contact Test Using the Activation Energy of Steady-State Space-Charge-Limited Current,” Physica Status Solidi (B), Vol. 85, No. 2, 1984, pp. 619-625.
 A. Bozhko, M. Shupegin, and T. Takagi, “Space-charge- limited Current in Hydrogenated Amorphous Carbon Films Containing Silicon and Oxygen,” Diamond and Related. Materials, Vol. 11, No. 10, October 2002, pp. 1753-1759. doi.10.1016/S0925-9635(02)00156-5
 C. Godet, “Hopping Model for Charge Transport in Amo- rphous Carbon,” Philosophical Magazine Part B, Vol. 81, No. 2, February 2001, pp. 205-222.
 O. ?zdemir, M. Anutgan, T. Aliyeva-Anutgan, ?. At?lgan and B. Kat?rc?o?lu, “Electrical Transport Mechanism in Boron Nitride Thin Film,” Journal of Non-Crystalline Solids, Vol. 355, No. 14-15, 1 June 2009, pp. 851-859.
 O. ?zdemir, ?. At?lgan, B. Akao?lu, K. Sel and B. Kat?rc?o?lu, “Frequency Dependence of Conductivity in Intrinsic Amorphous Silicon Carbide Film, Assessed Through Admittance Measurement of Metal Insulator Semiconductor Structure,” Thin Solid Films, Vol. 497, No. 1-2, 21 February 2006, pp. 149-156.
 O. ?zdemir, S. ?zder, ?. At?lgan and B. Kat?rc?o?lu, “Admittance Analyis of an MIS Structure Made with PECVD Deposited A-SiNx:H Films,” Journal of Non- Crystalline Solids, Vol. 249, No. 2-3, 2 July 1999, pp. 131-144
 S. ?zder, “Investigation of SiO2/p-Si Structure by DLTS and Various Admittance Techniques,” Ph.D. Dissertation,