Characterization of silicon dioxide films deposited at low pressure and temperature in a helicon diffusion reactor

Abstract

Silicon dioxide films have been deposited at low pressure (a few millitorr) and low substrate temperature (<200 °C) by oxygen/silane helicon diffusion radio frequency plasmas. High deposition rates (20–80 nm/min) are achieved at 800 W rf source power. The effect of the oxygen/silane flow rate ratio (R) on the film properties has been investigated: characterization of the deposited films has been carried out by in situ ellipsometry, ex situ Fourier transform infrared spectroscopy, Rutherford backscattering, x-ray photoelectron spectroscopy (XPS), and chemical etch rate measurements (P etch) and the results have been compared to thermally grown oxide. The deposition kinetics has a great effect on the internal film structure: for films presenting a good stoichiometry ([O]/[Si]≥1.95 for R≥3), a decrease in the deposition rate is accompanied by a decrease of the refractive index, P-etch rate and XPS line width and by an increase of the Si–O stretching peak frequency toward the thermal oxide respective values. A sufficient oxygen/silane flow rate ratio (R=10) leads to stoichiometric films which exhibit good optical properties. Small differences in the P-etch rate, XPS linewidth, and infrared stretching peak frequency are still observed between our stoichiometric plasma deposited film and a thermally grown oxide film.

Effect of ion bombardment on the structural and optical properties of TiO2 thin films deposited from oxygen/titanium tetraisopropoxide inductively coupled plasma

“…TiO 2 films (200 to 300 nm thick) were grown on silicon (100) substrate by a PECVD system consisting of a helicon reactor, which has been detailed in the earlier publications [33][34].…”

Effect of growth interruptions on TiO 2 films deposited by plasma enhanced chemical vapour deposition

“…The TiO 2 films were deposited on silicon (100) substrate (Si) by a PECVD system detailed in earlier publications [30,31], consisting of a diffusion chamber and a low pressure high density plasma helicon reactor. Briefly, this reactor consists of a glass tube and an external helicon antenna, stuck to the tube, these two elements are surrounded themselves by a coil which creates an axial D.C. magnetic field (about 5 Â 10 À3 T in the center of the source) to confine the electrons [32].…”

Low-temperature processing of SiO 2 thin films by HD-PECVD technique for gate dielectric applications

“…Several variations of this technique, such as remote and ECR plasma CVD, are being extensively investigated for low temperature processing of SiO 2 thin films. [2][3][4][5][6][7][8] In conventional PECVD reactors, the role of plasma generation and wafer biasing are coupled: higher input power (to increase the plasma density) simultaneously increases the sheath-bias potential. Plasma ions falling through these potentials can cause unacceptably high device damage.…”