By Melbourne Centre for Nanofabrication
The process Sputtering is a physical vapour deposition method that involves depositing thin films in a vacuum environment. During this process, a solid material and substrate are positioned separately within a vacuum system. A high-energy argon ion plasma stream is targeted at the material, resulting in the subject material being ejected and deposited onto the substrate, creating a thin film. As this is not an evaporative process, the temperatures required for sputtering are lower than evaporation methods. This makes it one of the most flexible deposition processes and it is particularly useful for depositing materials with a high melting point or a mixture of materials, as compounds that may evaporate at different rates, can be sputtered at the same rate. Certain processes will benefit from improved film adhesion due to higher impact energy. The uses The sputtering process is used extensively in the semiconductor industry, screen displays, photovoltaics and magnetic data storage. Sputtering can be used to deposit a wide variety of thin films including metals, oxides, nitrides and alloys. The instruments MCN has three main sputter deposition systems, the Intlvac Nanochrome Pulsed DC system, the Anatech Hummer BC-20 RF/DC system, and the AJA-2200-HY combinatorial system. The Intlvac and Anatech systems consist of an RF and DC power supply and support samples sizes up to 8 inch diameter. Different process gases are available including argon, oxygen and nitrogen, allowing the deposition of pure metals, oxides, nitrides, alloys and customised combinatorial compositions. In addition, the two systems also support ion beam assisted deposition. The thickness of the coating can vary from ~10nm up to 5µm (thickness greater than 1µm should be discussed with the process engineer). The materials library currently available includes metals (Al, Cr, Ti, Cu, W, Mo, Co, Ni, Fe), oxides (ZnO, TiO2, WoO3, MoO3, CoO, Al2O3) and nitrides (AlN, TiN). The AJA-2200-HY is a hybrid thin film deposition system which has six sputter targets, one off-axis sputter target, e-beam source, in-situ ellipsometery and RHEED scanning capability. It is also fitted with a X-Y stage and masking (combinatorial function). MCN also has 3 small sputter units which primarily support characterisation sample prep (Leica EM ACE600, Quorum Q-series, & Pt DSR Unit).
