Robert A. Auerbach

Preparation of metallic organotin films by glow discharge polymerization and their properties

Abstract Thin (1000 A) reflective (mirror-like) tin films are formed by introducing tetramethyltin and O2 gas into a glow discharge. The resulting films show a sheet conductivity in the range of about 102–104 Ω−1 cm−1. The films are stable at ambient conditions for more than 1 year (without any change in sheet conductivity). Heating the films up to about 63°C does not change the conductivity appreciably, but prolonged heating at higher temperatures increases the conductivity irreversibly. Electron spectroscopy for chemical analysis results show a trace amount of carbon on the surface of the film, but the bulk of the film is essentially carbon free. Electron diffraction and X-ray photographs of the films are indexed as β-Sn. The films adhere strongly to metals, ceramics, composites and plastics and act as good water vapor barriers (1.76 × 10−14 cm3 (STP) cm cm−2 s−1 cmHg−1 where STP denotes standard temperature and pressure). The effect of the flow rate of O2 on the film characteristics is discussed.

Formation and properties of metallic organotin films

Abstract Semiconductive and conductive films of metallic appearance are formed by glow discharge of appropriate organometallic compounds. Tetramethyltin is used as a starting compound for the film-forming experiments. The resulting films contain carbon, tin and hydrogen with a carbon-to-tin atomic ratio of 2.5 or less. These films are semiconductors with conductivities between 2 × 10-1 and 1 × 10 -2 Ω -1 cm -1 . Transmission electron microscopy shows the films to be amorphous. Films of a certain composition are transformed to β-Sn on exposure to an electron beam. Thermal treatment increases the conductivity gradually to values of about 1 × 10 2 Ω -1 cm -1 .

Interface composition and adhesion of glow‐discharge‐formed organo–tin polymers

The interface composition and bonding of thin organo–tin polymers, plasma‐deposited on Al, are determined by AES, ESCA, and pull testing. A tin oxide species is formed between the bulk organo–tin polymer and the Al surface within an interfacial region of about 10 nm. This is evidenced by the change in the profile of the Sn‐MNN Auger signal and by the energy shift of the Sn 3d3/2 and 3d5/2 peaks in the ESCA spectrum. No tin oxide formation is observed at the interface of organo–tin films deposited under similar conditions on stainless steel. The composition at the interface is also shown to depend on the position of the sample in the glow discharge during film deposition.

The composition of organo-tin polymer films on metallic substrate materials☆

Abstract Glow discharge films with various ratios of carbon to tin were deposited on various metals and on glass. The ratio of carbon to tin was determined quantitatively by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The AES data correlated well with the XPS data. The X-ray beam and electron impact effects on organo-tin films influence the composition and are discussed in detail. The ratio of carbon to tin was not constant throughout the glow discharge reactor and this inhomogeneity is accounted for by the prevalence of “atomic” polymerization rather than “molecular” polymerization. We demonstrated that the substrate material had a definite influence on the composition of the films.