Reactive Sputtering

Vanadium dioxide is well known for its semiconductor-to-metal transition at 67°C, which produces dramatic changes in optical and electrical properties. Some applications of VO2 thin films are transparent conductors, holographic media, electrical switching, and thermal stabilizing coatings. Reactive magnetron sputtering was chosen as the deposition technique, because of it potential for producing surface area thin films is uniform thickness, and higher deposition rates than conventional reactive diode sputtering. However, reactive sputtering conditions for VO2 formation are unstable and difficult to control because they occur when the target undergoes massive oxidation. I have succeeded in producing VO2 thin films be reactive magnetron sputtering that exhibit a semiconductor-to-metal resistivity ratio of 10^4, compared to 10^5 for single crystals. This thesis will show the behavior of V-O reactive magnetron sputtering, explain its behavior using computer simulations, and demonstrate how the process can be used to grow VO2 thin films.

İnce film üretim teknikleri
Kopartma (Sputtering) yöntemi
Kopartma (Sputtering) sisteminin temel bileşenleri
Kopartma (Sputtering) yönteminin parametreleri
Kopartma (Sputtering) sisteminin çalışma prensibi
Kopartma (Sputtering) yönteminin uygulandığı sistemler
Magnetron kopartma (sputtering) sistemi
DC/RF (diyot) kopartma (sputtering) sistemi
Triyod kopartma (sputtering) sistemi
İyon Demeti kopartma (sputtering) Sistemi
Magnetron ve magnetron olmayan kopartma sistemleri arasındaki fark
Kullanılan gazlar
Uygulama alanları
Avantajları
Dezavantajları
Özet
Kaynaklar
Teşekkür

This paper reports on the structural, mechanical and tribological properties of molybdenum–copper nanocomposite films ‘doped’ with small amounts of nitrogen, which contain either no nitride phase (i.e. the nitrogen is held in interstitial solid solution, mainly in molybdenum) or small amounts of lower nitrides (i.e. Mo2N). All films were deposited on Si wafers, AISI M2 high speed steel and AISI 316 stainless steel by reactive sputtering using a hot-filament-enhanced dc unbalanced magnetron system. A systematic approach was adopted to investigate the evolution of metal/metal and ceramic/metal phase combinations with increasing nitrogen content (up to ∼ 40 at.% N) in the film. Coating composition and microstructure were determined by cross-sectional TEM, SEM and XPS. XRD was used to identify (where possible) metallic and metal-nitride phases. Mechanical properties such as hardness and elastic modulus were determined by low load Knoop and instrumented Vickers indentation measurements. Reciprocating sliding, micro-abrasion and impact tests were performed to assess tribological performance.It was found that increasing the nitrogen gas flow rate from 0 to 15 sccm (and therefore nitrogen content in the film from 0 to 24 at.% N), refined significantly the coating microstructure from columnar to a dense and more equiaxed morphology, increasing the hardness whilst maintaining (almost constant) elastic modulus values, close to that of molybdenum metal. Further increases in the nitrogen gas flow rate resulted in films that appeared to contain significant fractions of the Mo2N ceramic phase. SEM and cross-sectional TEM analyses of the film deposited at a nitrogen flow rate of 20 sccm (containing ∼36 at.% N) demonstrated a microstructure consisting of 50–100 nm wide columns, which contain small regions of contrast in dark-field images, of the order of 3–5 nm wide. A maximum hardness of 32 GPa and the highest hardness/modulus ratio was however found in the (predominantly metallic) film deposited at a nitrogen gas flow rate of 15 sccm. This film also performed best in both micro-abrasion and impact wear tests; in contrast, the ‘ceramic’ film (deposited at 20 sccm nitrogen flow rate) performed better in reciprocating sliding wear.

Thin films of iridium oxide were deposited on silicon and borosilicate glass substrates by pulsed-direct-current (pulsed-DC) reactive sputtering of iridium metal in an oxygen-containing atmosphere. Optimum deposition conditions were identified in terms of plasma pulsing conditions, oxygen partial pressures, and substrate temperature. The films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and Rutherford backscattering spectroscopy. According to

Titanium dioxide thin films have many interesting properties and are used in various applications. High refractive index of titania makes it attractive for the glass coating industry, where it is used in low-emissivity and antireflective coatings. Magnetron sputtering is the most common deposition technique for large area coatings and a high deposition rate is therefore of obvious interest. It has been shown previously that high rate can be achieved using substoichiometric targets. This work deals with reactive magnetron sputtering of titanium oxide films from TiOx targets with different oxygen contents.The deposition rate and hysteresis behaviour are disclosed. Films were prepared at various oxygen flows and all films were deposited onto glass and silicon substrates with no external heating. The elemental compositions and structures of deposited films were evaluated by means of X-ray photoelectron spectroscopy, elastic recoil detection analysis and X-ray diffraction. All deposited films were X-ray amorphous. No significant effect of the target composition on the optical properties of coatings was observed. However, the residual atmosphere is shown to contribute to the oxidation of growing films.

Arc and glow discharges are defined based on their cathode processes. Arcs are characterized by collective electron emission, which can be stationary with hot cathodes (thermionic arcs), or non-stationary with cold cathodes (cathodic arcs). A brief review on cathodic arc properties serves as the starting point to better understand arcing phenomena in sputtering. Although arcing occurs in both metal and