High-temperature sputtering

A high temperature optical fiber thermometer has beea developed (32,33). It coasists of a sputtered iridium blackbody tip oa a single crystal sapphire laser. Such a device has beea showa to be accurate to within 0.03° C at 1000°C. 

Sputtering is an important thin-film process used extensively in the semiconductor and hard-coating industries and for decorative and jewelry coatings. PlP] Excellent coatings of refractory compounds and metals can be readily produced with good adhesion and composition control without the high temperature requirements of CVD. 

The talk will briefly review some of these developments ranging from high temperature equilibrium plasmas to cool plasmas, PECVD, ion implantation, ion beam mixing and ion assisted etching and deposition. Brief consideration will also be given to sputtering and ionised cluster beam deposition techniques in inorganic synthesis. 

The addition of In and Ga and selenization at high temperature were crucial in obtaining the 13.4%-efficient device. Photovoltaic device fabrication was completed by a CBD of about 500 A of CdS, followed by RF sputtering of 500 A of intrinsic ZnO and 3500 A of Al203-doped conducting ZnO. Bilayer Ni/Al top contacts were deposited in an e-beam system. The final step in the fabrication sequence is the deposition of lOOnm of MgF2 as an antirellection coating. 

Such changes in the defect population can be critical in device manufacture and operation. For example, a thin him of an oxide such as SiO laid down in a vacuum may have a large population of anion vacancy point defects present. Similarly, a him deposited by sputtering in an inert atmosphere may incorporate both vacancies and inert gas interstitial atoms into the structure. When these hlms are subsequently exposed to different conditions, for example, moist air at high temperatures, changes in the point defect population will result in dimensional changes that can cause the him to buckle or tear. 

Iron oxide (Fe Oj) and tungsten oxide (WO ) films have been studied and developed as candidate semiconductor materials for the PEC junction (photoanode). High-temperature synthesis methods, as reported for some high-performance metal oxides, have been found incompatible with multijunction device fabricatioa A low-temperature reactive sputtering process has been developed instead. In the parameter space investigated so far, the optoelectronic properties of WO3 films were superior to those of Fe Oj films, which showed high recombination of photogenerated carriers (Miller et al., 2004). 

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