Plasma-and thermal-assisted chemical vapor deposited (CVD) tetraethylorthosilicate (TEOS) oxide films were deposited on silicon substrates using a single-wafer reactor. The deposition kinetics of both plasma and thermal CVD processes were studied as a function of temperature. Film properties and bonding structure were analyzed for as-deposited and annealed films using Fourier transform infrared spectroscopy (FTIR), Auger, x-ray photoelectron spectroscopy (XPS), and nuclear reaction analysis (NRA) techniques. The thermal TEOS films were found to be more porous and to contain more hydrogen, but were more conformal than plasma-deposited TEOS films. Without a plasma, thermal temperatures can assist gas-phase reactions between ozone and TEOS (oxidation) to form conformal oxide films at as low as 200~ With a plasma, both gas-phase and subsequent surface CVD reactions between TEOS, ozone, and oxygen are substantially enhanced, thus result in CVD films with higher quality.Low temperature plasma and thermal CVD silicon dioxide films have many applications in high density, advanced semiconductor device fabrication. For good stepcoverage, high mobility organosilicon reactants such as TEOS are normally used (1, 2). In this paper, the plasma and thermally assisted CVD reactions between TEOS, ozone, and oxygen were studied and analyzed as a function of process parameters. The effect of processing temperature on the deposition kinetics and the correlation to film quality was examined in detail. Variations of both plasma and thermally deposited films were analyzed before and after densification annealing by FrIR, Auger, XPS, and NRA. In addition, other film properties such as wet and dry etch characteristics, stress and step-coverage were also investigated. ExperimentalPlasma and thermal CVD TEOS oxide films were deposited on silicon substrates using a single-wafer deposition system as shown in Fig. 1. Oxygen, TEOS, and helium (as a carrier gas bubbled through the TEOS) were used as deposition gases for plasma-assisted (13.56 MHz) CVD processing. TEOS, ozone, and oxygen were used for thermal CVD processing. The temperature of the TEOS ampul and the helium/TEOS gas line was maintained at 35~ during the deposition process. Careful temperature control of the helium/TEOS is required to reduce possible TEOS droplet formation in gas line. The TEOS droplets will result in incomplete TEOS decomposition and carbon contamination in the film.Typical deposition conditions for both plasma and thermal films appear in Table I. Thermal CVD reactions between TEOS and ozone were studied as a function of substrate temperature from 200 ~ to 440~ Plasma CVD reactions between TEOS and oxygen were studied for substrate temperatures from 50 ~ to 440~ All films were deposited on bare silicon p-type substrates. Film thickness and refractive index were measured using a He-Ne laser ellipsometer. FTIR analysis was performed with 500 nm films deposited on bare silicon substrates. Background absorption of the substrate was subtracted to obtain the bulk film s...

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Films of Si:,N4 containing excess Si were prepared by plasma-enhanced chemical vapor deposition at 350~ by the glow discharge reaction of gaseous Sill4 (1.9% in helium) in NH:~ in a tube-type, hot wall reactor at 450 kHz RF frequency. The amount of silicon in the Si:,N4 films was adjusted by varying the reactant gas-phase ratio. The deposited films had a refractive index range of 1.90-2.70. Auger analysis (depth profiles) showed -that the Si concentration in the films increased with refractive index. A small amount of oxygen contamination was observed on all film surfaces. X-ray photoelectron spectroscopy measurements showed the presence of excess silicon, probably present as amorphous Si clusters in films with a high refractive index and oxygen contamination in all deposited film surfaces. Fourier transform infrared and nuclear reaction analysis for hydrogen showed that the hydrogen concentration ranged from 13 to 22 atomic percent and the hydrogen concentration decreased monotonically with increased refractive index. Etch rates of deposited films in CF4/O~ glow discharge decrease monotonically with decreased hydrogen and increased silicon concentration in the films.

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