WJCMP  Vol.6 No.1 , February 2016
Opto-Structural Properties of Silicon Nitride Thin Films Deposited by ECR-PECVD
Amorphous hydrogenated silicon nitride thin films a-SiNx:H (abbreviated later by SiNx) were deposited by Electron Cyclotron Resonance plasma enhanced chemical vapor deposition method (ECR-PECVD). By changing ratio of gas flow (R = NH3/SiH4) in the reactor chamber different stoichiometric layers x = [N]/[Si] ([N] and [Si] atomic concentrations) are successfully deposited. Part of the obtained films has subsequently undergone rapid thermal annealing RTA (800°C/1 s) using halogen lamps. Optical and structural characterizations are then achieved by spectroscopic ellipsometry (SE), ion beam analysis and infrared absorption techniques. The SE measurements show that the tuning character of their refractive index n(λ) with stoichiometry x and their non-absorption properties in the range of 250 - 850 nm expect for Si-rich SiNx films in the ultraviolet UV range. The stoichiometry x and its depth profile are determined by Rutherford backscattering spectrometry (RBS) while the hydrogen profile (atomic concentration) is determined by Elastic Recoil Detection Analysis (ERDA). Vibrational characteristics of the Si-N, Si-H and N-H chemical bonds in the silicon nitride matrix are investigated by infrared absorption. An atomic hydrogen fraction ranging from 12% to 22% uniformly distributed as evaluated by ERDA is depending inversely on the stoichiometry x ranging from 0.34 to 1.46 as evaluated by RBS for the studied SiNx films. The hydrogen loss after RTA process and its out-diffusion depend strongly on the chemical structure of the films and less on the initial hydrogen concentration. A large hydrogen loss was noted for non-thermally stable Si-rich SiNx films. Rich nitrogen films are less sensitive to rapid thermal process.

Cite this paper
Charifi, H. , Slaoui, A. , Stoquert, J. , Chaib, H. and Hannour, A. (2016) Opto-Structural Properties of Silicon Nitride Thin Films Deposited by ECR-PECVD. World Journal of Condensed Matter Physics, 6, 7-16. doi: 10.4236/wjcmp.2016.61002.
[1]   Kim, Y.K. and Rudd, M.E. (1994) Binary-Encounter Dipole Model for Electron Impact Ionization. Physical Review A, 50, 3954-3967.

[2]   Smith, D.L. (1993) Controlling the Plasma Chemistry of Silicon Nitride and Oxide Deposition from Silane. Journal of Vacuum Science & Technology A, 11, 1843.

[3]   Smith, D.L., Alimonda, A.S. and von Preissig, F.J. (1990) Mechanism of SiNxHy deposition from N2-SiH4 Plasma. Journal of Vacuum Science & Technology B, 8, 551.

[4]   Smith, D.L., Alimonda, A.S., Chau-Chen, C., Ready, S.E. and Wacker, B. (1990) Mechanism of SiNxHy Deposition from NH3-SiH4 Plasma. Journal of the Electrochemical Society, 137, 614-623.

[5]   Hezel, R. and Schorner, R. (1981) Plasma Si Nitride—A Promising Dielectric to Achieve High-Quality Silicon MIS/IL Solar Cells. Journal of Applied Physics, 52, 3076.

[6]   Leguijt, C., et al. (1996) Low Temperature Surface Passivation for Silicon Solar Cells. Solar Energy Materials and Solar Cells, 40, 297-345.

[7]   Aberle, A.G. and Hezel, R. (1997) Progress in Low-Temperature Surface Passivation of Silicon Solar Cells Using Remote-Plasma Silicon Nitride. Progress in Photovoltaics, 5, 29.

[8]   Hofmann, M., Schneiderlöchner, E., Wolke, W. and Preu, R. (2004) Silicon Nitride-Silicon Oxide Stacks for Solar Cell Rear Side Passivation. 19th European Photovoltaic Solar Energy Conference Proceeding, Paris, 7-11 June 2004, 1037-1040.

[9]   Duerinckx, F. and Szlufcik, J. (2002) Defect Passivation of Industrial Multicrystalline Solar Cells Based on PECVD Silicon Nitride. Solar Energy Materials and Solar Cells, 72, 231-246.

[10]   Wolf, S., Agostinelli, G. and Beaucarne, G. (2005) Influence of Stoichiometry of Direct Plasma-Enhanced Chemical Vapor Deposited [SiNx] Films and Silicon Substrate Surface Roughness on Surface Passivation. Journal of Applied Physics, 97, Article ID: 063303.

[11]   Aberle, G. (2000) Progress in Photovoltaic. Research and Applications, 8, 473-487.

[12]   Jellison Jr., G.E. and Modine, F.A. (1996) Parameterization of the Optical Functions of Amorphous Materials in the Interband Region. Applied Physics Letters, 69, 371-373, 2137.

[13]   Tompkins, H.G. and Irene, E.A. (2005) Chapter 2-3: Handbook of Ellipsometry. William Andrew Publishing, Springer-Verlag, Norwich.

[14]   Soppe, W., Rieffe, H. and Weeber, A. (2005) Bulk and Surface Passivation of Silicon Solar Cells Accomplished by Silicon Nitride Deposited on Industrial Scale by Microwave PECVD. Progress in Photovoltaics: Research and Applications, 13, 551-569.

[15]   Yin, Z. and Smith, F.W. (1990) Optical Dielectric Function and Infrared Absorption of Hydrogenated Amorphous Silicon Nitride Films: Experimental Results and Effective-Medium-Approximation Analysis. Physical Review B, 42, 3666-3675.

[16]   Ingo, G.M., Zacchetti, N., Della Sala, D. and Coluzza, C. (1989) X-Ray Photoelectrons Spectroscopy Investigation on the Chemical Structure of Amorphous Silicon Nitride (a-SiNx). Journal of Vacuum Science and Technology, 7, 3048-3055.

[17]   Philipp, H.R. (1973) Optical Properties of Silicon Nitride. Journal of the Electrochemical Society, 120, 295-300.

[18]   Robertson, J. and Powell, M.J. (1983) Gap States in Silicon Nitride. Applied Physics Letters, 44, 415-417.

[19]   Dupont, G., Caquineau, H., Despax, B., Berjoan, R. and Dollet, A. (1997) Structural Properties of N-Rich a-Si-N:H Films with Low Electron-Trapping Rate. Journal of Physics D: Applied Physics, 30, 1064-1076.

[20]   Robertson, J., Warren, W.L. and Kanicki, J. (1995) Nature of Si and N Dangling Bonds in Silicon Nitride. Journal of Non-Crystalline Solids, 187, 297-300.

[21]   Hong, J., Kessels, W.M.M., Soppe, W.J., Rieffe, H.C., Weeber, A.W. and Van Desanden, M.C.M. (2003) Structural Film Characteristics Related to the Passivation Properties of High-Rate (>0.5 nm/s) Plasma Deposited a-SiNx:H. Proceedings of 3rd World Conference on Photovoltaic Energy Conversion, Osaka, 11-18 May 2003, 1158-1161.

[22]   Cai, L., Rohatgi, A., Ang, D. and El-Sayed, M.A. (1996) Effects of Rapid Thermal Anneal on Refractive Index and Hydrogen Content of Plasma-Enhanced Chemical Vapor Deposited Silicon Nitride Films. Journal of Applied Physics, 80, 5384-5388.

[23]   Bustarret, E., Bensouda, M., Habrard, M.C. and Bruyère, J.C. (1988) Configurational Statistics in a-SixNyHz Alloys: A Quantitative Bonding Analysis. Physical Review B, 38, 8171-8184.

[24]   Dauwe, S. (2003) Low Temperature Surface Passivation of Crystalline Silicon and Its Application to the Rear Side of Solar Cells. PhD Thesis, Hannover University, Hannover.

[25]   Mäckel, H. and Lüdemann, R. (2002) Detailed Study of the Composition of Hydrogenated SiNx Layers for High-Quality Silicon Surface Passivation. Journal of Applied Physics, 92, 2602.

[26]   Lauinger, T., Moschner, J., Aberle, A.G. and Hezel, R. (1998) Optimization and Characterization of Remote Plasma-Enhanced Chemical Vapor Deposition Silicon Nitride for the Passivation of P-Type Crystalline Silicon Surfaces. Journal of Vacuum Science & Technology A, 16, 530.

[27]   Lauinger, T., Aberle, A.G. and Hezel, R. (1997) Comparison of Direct and Remote PECVD Silicon Nitride Films for Low-Temperature Surface Passivation of P-Type Crystalline Silicon. Proceedings of the 14th European Photovoltaic Solar Energy Conference, Barcelona, 30 June-4 July 1997, 853.

[28]   Morello, G. (1995) Hydrogen Content of Amorphous PECVD SiNx:H Films by Infrared Spectroscopy and Hydrogen Forward Scattering Results. Journal of Non-Crystalline Solids, 187, pp. 308-312.

[29]   Lanford, W.A. and Rand, M.J. (1978) The Hydrogen Content of Plasma-Deposited Silicon Nitride. Journal of Applied Physics, 49, 2473-2477.

[30]   Shih, A., Yeh, S.-H., Lee, S.-C. and Yang, T.R. (2001) Structural Differences between Deuterated and Hydrogenated Silicon Nitride/Oxynitride. Journal of Applied Physics, 89, 5355.

[31]   Demichelis, F., Giorgis, F. and Perri, C.F. (1996) Compositional and Structural Analysis of Hydrogenated Amorphous Silicon—Nitrogen Alloys Prepared by Plasma-Enhanced Chemical Vapour Deposition. Philosophical Magazine Part B, 74, 155-168.

[32]   Verlaan, V., van der Werf, C.H.M., Arnoldbik, W.M., Goldbach, H.D. and Schropp, R.E.I. (2006) Unambiguous Determination of Fourier-Transform Infrared Spectroscopy Proportionality Factors: The Case of Silicon Nitride. Physical Review B, 73, Article ID: 195333.

[33]   Fujita, S., Toyoshima, H. and Sasaki, A. (1988) Bonding Configuration of Fluorine in Fluorinated Silicon Nitride Films. Journal of Applied Physics, 64, 3481.

[34]   Denisse, C.M.M., Troost, K.Z., Habraken, F.H.P.M., van der Weg, W.F. and Hendriks, M. (1986) Annealing of Plasma Silicon Oxynitride Films. Journal of Applied Physics, 60, 2543-2547.

[35]   Nijs, J., Szlufcik, J., Poortmans, J., Sivoththaman, S. and Mertens, R.P. (1999) Advanced Manufacturing Concepts for Crystalline Silicon Solar Cells. IEEE Transactions on Electron Devices, 46, 1948-1969.

[36]   Jeong, J.-W., Rosenblum, M.D., Kalejs, J.P. and Rohatgi, A. (2000) Hydrogenation of Defects in Edge-Defined Film-Fed Grown Aluminum-Enhanced Plasma Enhanced Chemical Vapor Deposited Silicon Nitride Multicrystalline Silicon. Journal of Applied Physics, 87, 7551-7557.

[37]   Jiang, F., Stavola, M., Rohatgi, A., Kim, D., Holt, J., Atwater, H. and Kalejs, J. (2003) Hydrogenation of Si from SiNx:H Films: Characterization of H Introduced into the Si. Applied Physics Letters, 83, 931-933.

[38]   Dekkers, H.F.W., Beaucarne, G., Charifi, H. and Slaoui, A. (2006) Molecular Hydrogen Formation in Hydrogenated Silicon Nitride. Applied Physics Letters, 89, Article ID: 211914.