Harald Suhr

Thin copper films by plasma CVD using copper-hexafluoro-acetylacetonate

Thin copper films are produced by plasma-enhanced chemical vapour deposition (PECVD) using copper-hexafluoro-acetylacetonate (CF3-CO-CH=C(O)-CF3)2Cu in argon-hydrogen mixtures. Film qualities depend on power density, gas flow, and substrate temperature. ESCA spectra show no Cu-F bonds in the films.

Application of nonequilibrium plasmas in organic chemistry

All organic molecules having similar ionization and dissociation energies, are sensitive to elevated temperatures and can easily be destroyed by plasma. Under selective experimental conditions, however, organic plasma chemistry can be a valuable synthetic method. Main areas of applications are the generation of reactive species, isomerizations, eliminations, cyclisations, condensations, and multistep reactions. During the last decade numerous preparative methods have been reported. These are summarized together with many unpublished results from the Tübingen laboratory. In addition reaction mechanisms, selectivities, kinetics, economics, possibilities, and limitations of organic plasma chemistry are discussed.

Deposition of copper oxide (Cu2O, CuO) thin films at high temperatures by plasma-enhanced CVD

Copper-oxide films are deposited by plasma-enhanced CVD using copper acetylacetonate as a precursor. The influence of various experimental parameters on deposition rate, film composition and resistivity have been studied. The substrate temperature and the bias are the parameters which affect these properties the most. An increase of the substrate temperature changes the phases of the deposit from Cu2O-CuO over Cu2O to Cu. At temperatures ≧500° C the deposition rates are high but the films consist mainly of metallic Cu. A negative bias enhances the deposition rate only slightly but has a strong effect on the film composition and can completely balance the oxygen deficiency. At a bias of −120 V the films consist of pure CuO even at temperatures ≧500° C.

Thin palladium films prepared by metal−organic plasma-enhanced chemical vapour deposition

Abstract A method for the deposition of palladium films using the allylcyclopentadienyl palladium complex is reported. In a plasma-enhanced chemical vapour deposition process bright metallic films can be produced at low temperatures. The resistivity of these films approaches that of bulk palladium. If oxygen is used as the carrier gas, the films consist of PdO.

Thin Zirconium Nitride Films Prepared by Plasma-Enhanced CVD

Thin films of zirconium nitride have been deposited at temperatures as low as 573 K by PECVD using tetrakis(diethylamido)zirconium, Zr[N(C2H5)2]4 as precursor. The influence of the various experimental parameters on film properties and deposition rates has been studied. Under most experimental conditions hard coatings of good adherence and low carbon contamination resulted.

Thin yttrium and rare earth oxide films produced by plasma enhanced CVD of novel organometallic π-complexes

Novel volatile cyclooctatetraenyl-pentamethylcyclopentadienyl sandwich complexes have been used as precursors to deposit thin yttrium and rare earth oxide films by means of PECVD. These compounds form pure oxide films in plasmas of argon/oxygen or argon/water-vapour, in nitrous oxide, and carbon dioxide at substrate temperatures of 350–400° C and power densities of 1.0–1.5 W/cm2.The films were characterized by metal analysis, carbon analysis, XPS, CTEM electron diffraction, SEM micrographs, and FTIR spectra.

Hydrogen sulfide dissociation in ozonizer discharges and operation of ozonizers at elevated temperatures

A high-temperature ozonizer device has been developed to stud v the conversion of hydrogen sulfide (H2S) into elemental sulfur and hydrogen. To allow for continuous operation, the process must be carried out at temperatures high enough to remove the sulfur in the liquid (=156°C) or in the vapor state (>435°C). A double quartz wall ozonizer which tolerates the high electrical and chemical requirements was constructed. Its electrical characteristics in the temperature range of 130–560°C and the influence of experimental parameters on conversion and energetic elficiency are described.

Application of a rotating high-pressure glow discharge for the dissociation of hydrogen sulfide

The dissociation of hydrogen sulfide has been studied in an atmospheric-pressure glow discharge rotating between concentric electrodes in an axial magnetic field. Though the electrodes were heated to remove the sulfur formed in the discharge, stable operation was possible. The characteristics of the discharge and the influence of experimental parameters on the conversion of hydrogen sulfide and the energy efficiency are reported.

Plasma-enhanced chemical vapour deposition of thin GeO2, SnOx, GeO2SnOx, and In2O3 films

Abstract Thin films of SnOx, GeO2, mixed GexSnyOz, and In2O3 have been deposited by plasma-enhanced chemical vapour deposition (PECVD) of the methyl compounds Sn(CH3)4, Ge(CH3)4 and In(CH3)3. Indium oxide films have also been prepared from In(thd)3 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) by PECVD.

Applications and trends of nonequilibrium plasma chemistry with organic and organometallic compounds

The possibilities and limitations of available apparatus for nonequilibrium discharges are discussed. Especially for synthetic work there is a lack of suitable equipment. The unique possibilities which plasmas offer to chemistry are demonstrated by examples from the homogeneous gas phase, and from plasma liquid and plasma solid interactions. Various applications and major trends are being described. The most rapidly increasing field of plasma chemistry is presently the formation of thin films of metals, oxides, carbides, or nitrides by plasma enhanced CVD. The latest results, and especially the use of organometallic compounds and starting material, are being discussed.