The Bonding Structure and Compositional Analysis of Plasma Enhanced and Low Pressure Chemical Vapor Deposited Silicon Dielectric Films

Abstract

Silicon dielectric films such as silicon nitride, oxide and oxynitride films deposited by Plasma Enhanced and Low Pressure Chemical Vapor Deposition (PECVD and LPCVD) processes were analyzed and compared using Fourier Transform Infrared (FTIR), X-ray Photoelectron, Auger, Electron Spin Resonance Spectroscopies and Nuclear Reaction Analysis for hydrogen. The plasma deposited films exhibit a more random structure with less long-range order and contain more hydrogen as compared to those of LPCVD films. However, marked similarities were observed in the bonding and its variation in films deposited by both processes. Analysis data indicates that the silicon oxynitride films (RI-1.75–1.78), deposited by both processes, may be the most stable oxynitride where mixed silicon oxynitride tetrahedral N2-Si-O2 bonding structures are most abundant.

The Characterization of Electron Cyclotron Resonance Plasma Deposited Silicon Nitride and Silicon Oxide Films

“…Table II shows the half-peak width comparison between ECR, thermal and plasma deposited nitride and oxide films. The FTIR spectra of both plasma and thermal silicon nitride and oxide films, used for comparison with ECR plasma-deposited films in this study, have appeared in recent publications (9)(10)(11)(12). The vibrational bands halfpeak width of the Si--N (880 cm -1) and Si--O (1065 cm -1) modes of the plasma films are normally broader, while those of ECR and thermal films are about the same.…”

Critical evaluation of the state of the art of the analysis of light elements in thin films demonstrated using the examples of SiOXNY and AlOXNY films (IUPAC Technical Report)

“…IR has been utilized for the comparison of films deposited by different deposition techniques [65]. In this publication, the films deposited by LPCVD showed a broad band as a combination of overlapping bands with various small maxima resulting from the Si-O and Si-N vibrations in the possible N-Si-O bonding environments, while the PECVD spectra showed wider absorption bands with less distinguishable Si-O and Si-N bands because of the more random bonding structure and the higher concentration of hydrogen.…”

“…Electron spin density measurements for unpaired electrons in [65] showed that films with a refractive index of 1.75-1.78 had the lowest spin density. The films were 1-2 µm thick and deposited on silicon substrates.…”

“…Depth profiles of 10-100 nm thick SiO X N Y films are shown in [65] as peak-to-peak heights vs. sputtering time. The films were sputtered with 1 keV Ar ions, but no details about the analysis parameters are given.…”

“…Nuclear reaction analysis was applied in [65] to determine hydrogen depth profiles of 50-100 nm thick films. LPCVD films showed concentrations of 2-4 at% and PECVD films had concentrations of 9-22 at% because of the lower substrate temperature.…”