Author(s)

Hicham Charifi^1*, Abdelilah Slaoui², Jean Paul Stoquert², Hassan Chaib³, Abdelkrim Hannour¹

¹Laboratory of Condensed Matter Physics and Nanomaterials for Renewable Energy, University Ibn Zohr, Agadir, Morocco.
²ICube, CNRS-Université de Strasbourg, Strasbourg, France.
³Research Group Materials and Energy, Polydisciplinary Faculty, Ibn Zohr University, Ouarzazate, Morocco.

Amorphous hydrogenated silicon nitride thin films a-SiN_x:H (abbreviated later by SiN_x) 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 SiN_x 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 SiN_x 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.

ECR-PECVD, Silicon Nitride

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.