Measurement of Sputtering Yields and Ion Beam Damage to Organic Thin Films with the Quartz Crystal Microbalance

An apparatus Is described for use in the measurement of sputtering yields of organic and organometallic thin films. The experimental arrangement involves the use of a dip-coated quartz crystal microbalance as the target for an ion beam. The apparatus is first tested using silver films deposited on the quartz crystal, and then extended to measurements on organic overlayers in the 3000-7000 Å thickness regime. Initial results for sputtering of thin films of polystyrene and polymethylmethacrylate using 1-KeV argon ions indicate that the sputter rate Initially decreases In an exponential fashion and ultimately becomes constant. These long time sputtering yields are distinctly different for the two polymers examined, although the rates of approach to these values are very similar. The results are Interpreted to be indicative of a common damage cross section for the collision of argon Ions with these polymer films of vastly different Initial structures.