OXIDATION OF TIN IN AN OXYGEN PLASMA ASHER

In previous work we have studied the thermal oxidation of titanium nitride. This involved temperatures of 350-degrees-C and greater, and times of hours. In this work, we study the oxidation of titanium nitride in a downstream plasma asher, where the sample temperature is about 200-degrees-C. For comparison to an older technology, we also include samples oxidized in a barrel asher where the sample temperature was about 100-degrees-C. Oxidation times of 16 min and less were studied. Thickness and optical constants were measured using ellipsometry along with Auger electron spectroscopy with argon ion etching for depth profiles. The growth kinetics are shown to be logarithmic. In the down-stream asher, films form in 90 s which would require 40 min at 450-degrees-C if grown thermally. We show that only the thinner films can be etched off in 50:1 HF.