Silicon Oxycarbide Films Produced by Remote Microwave Hydrogen Plasma CVD using a Tetramethyldisiloxane Precursor: Growth Kinetics, Structure, Surface Morphology, and Properties

Abstract

Amorphous hydrogenated silicon oxycarbide (a-SiCO:H) thin films are produced by remote microwave hydrogen plasma CVD using 1,1,3,3-tetramethyldisiloxane precursor. The effect of substrate temperature (T S ) on the chemical structure and some properties of resulting a-SiCO:H films is reported. The examination performed by infrared spectroscopy revealed that the increase in T S involves the elimination of organic moieties from the film and its transformation from polymer-like to ceramiclike high-crosslink-density material. Due to their small surface roughness, high density, and good optical transparency, the aSiCO:H films seem to be useful coatings for optical and electronic devices.

Atomic Hydrogen Induced Chemical Vapor Deposition of Silicon Oxycarbide Thin Films Derived from Diethoxymethylsilane Precursor

“…The radical products of equation (1) and equation (2) can readily recombine in the gas phase or on the growth surface to give Si-CH 2 -Si units, as illustrated by the equation 4: The oligomeric product of equation 3may subsequently undergo reactivation by H • radical and resulting disiloxane product after reaction with DEMS may produce disiloxane molecule equation (5). The same product can be obtained with the product of equation 3and the DEMS radical equation 1.…”

“…for silicon oxycarbide films produced from tetramethyldisiloxane precursor. [5,29] The negative activation energy indicates that the adsorption-desorption of film-forming species on the growth surface is the deposition rate-determining step. [43] The appearance of two slopes in the activation plot ( Figure 1b) may presumably be ascribed to a different nature of film-forming species produced in those temperature ranges and their various adsorption-desorption ability resulting therefrom.…”

“…Based on these structural studies and literature data [5] on the chemistry of alkoxysilane compounds, the following hypothetical mechanism of the most important elemental reactions can be proposed. As was well established for remote CVD plasma processes, [12] the DEMS precursor may undergo the activation, growth, and crosslinking reactions contributing to a-SiOC:H film growth.…”

“…This reaction may propagate the growth of a-SiOC:H film via their stepwise "had-to-tail" insertion forming the Si-O-Si and Si-C bonds, at the first stage in DEMS molecules adsorbed on the growth surface and then to the segments of growing film. This process may be exemplified by the elementary insertion reactions of the intermediates involving the Si-O and Si-C bonds, as described by equations (4,5), respectively, and further, in the same way, siloxane oligomers equation 6:…”

“…The T S influences not only a growth rate of the deposited films, but also some important physical and chemical properties. In our previous studies we have shown that remote hydrogen plasma (RP) CVD provides good conditions for generating silicon carbonitride (a-SiCN) and silicon oxycarbide (a-SiOC) materials which can be produced under similar conditions from TMDSN [27,28] and TMDSO [5,12,29] precursors, respectively. These thin films display excellent conformality of coverage, are robust, and may be used as, e.g., good oxidation or diffusion barriers.…”