| AVS 62nd International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF+2D+MG+NS-MoA |
| Session: | ALD, CVD, MLD, and PLD on Special Materials |
| Presenter: | Erik Johnson, LPICM-CNRS, Ecole Polytechnique, France |
| Authors: | JK. Wang, LPICM-CNRS, Ecole Polytechnique, France P. Bulkin, LPICM-CNRS, Ecole Polytechnique, France I. Florea, LPICM-CNRS, Ecole Polytechnique, France J.L. Maurice, LPICM-CNRS, Ecole Polytechnique, France E.V. Johnson, LPICM-CNRS, Ecole Polytechnique, France |
| Correspondent: | Click to Email |
For the growth of thin-film hydrogenated silicon by low temperature plasma-enhanced chemical vapor deposition (PECVD), SiF4 has recently attracted interest as a precursor for numerous reasons, most importantly due the resilient optoelectronic performance of the resulting layers and devices, even when grown in a slightly oxygen-contaminated growth environment. Nevertheless, many questions remain concerning the critical factors determining the quality of hydrogenated microcrystalline silicon (µc-Si:H) thin films grown from this precursor.
To advance knowledge on this subject, we present studies performed on two very different types of PECVD reactor: a standard capacitively coupled RF-PECVD reactor, using a process gas mixture consisting of Ar/SiF4/H2 and at deposition rates up to 4A/s, and a matrix-distributed electron cyclotron resonance (MDECR) PECVD reactor operating at much lower pressures but achieving a higher deposition rate (8 A/s) and using simply an SiF4/H2 mixture. In doing so, we reveal key details concerning the growth process. We underline recently obtained results concerning three critical experimental findings about the use of SiF4 as a growth precursor: (1) the importance of temperature for high-deposition rate, low-pressure conditions, (2) the vital role of ion bombardment energy on the quality of growth, and (3) the vastly increased challenge of the nucleation process when using high-density plasma processes. The films generated in these studies have furthermore been studied by cross sectional HR-TEM, revealing more specific details about the changing nature of the films during growth, and the dependence of these dynamics on the maximum ion energy impinging on the surface. These studies - along with residual gas analysis studies and optical emission spectroscopy results – allow us to examine the precise growth mechanism of such films when using an SiF4/H2 mixture.