ANALYSIS OF A-C/BH LAYERS DEPOSITED IN TDEV

Silicon collector samples were exposed close to the wall during trials of three boronization techniques - solid target boronization (STB), trimethyl boron (TMB) fueling and plasma-enhanced chemical vapor deposition (PECVD). The samples were analyzed by means of Auger electron spectroscopy and elastic recoil detection. The ''standard'', PECVD a-C/B:H layer was found to contain 84% carbon and 14% boron, with a H/(B+C) fraction of 0.55. The material deposited during TMB fueling contained 4-8% B (depending upon the sample orientation), 53-78% C, 6-12% O and 10-32% metals, with a H/(B+C) fraction in the 0.2-0.3 range. STB produced films containing 18-28% B, 56-61% C, 10% O and 4-17% metals, with values of 0.4-0.7 for H/(B+C). Consideration of the Fe/Ni ratio in the films leads us to speculate that the principal, short-term effect of the boronization on the metals contamination was to mask the stainless steel support structures of the main limiters.