AVS 54th International Symposium | |
Plasma Science and Technology | Wednesday Sessions |
Session PS1-WeA |
Session: | Plasma-Wall Interactions |
Presenter: | C.A. Wolden, Colorado School of Mines |
Authors: | M.T. Seman, Colorado School of Mines S.F. Szymanski, Colorado School of Mines C.A. Wolden, Colorado School of Mines |
Correspondent: | Click to Email |
Pulsed plasma-enhanced chemical vapor deposition (PECVD) has been engineered to deliver self-limiting growth (i.e. 1 Å/pulse) of metal oxides such as Ta2O5 and Al2O3. Pulsed PECVD may serve as a bridge between conventional ALD and PECVD, retaining monolayer control but with potentially much higher throughput. In this process the reactor walls are alternately exposed to atomic oxygen and metal precursors. The degree of adsorption in the latter step can dramatically influence both deposition rates and film quality. The impact of precursor adsorption on the plasma and gas-phase composition in these systems was measured using optical emission spectroscopy and quadrupole mass spectrometry, respectively. It is shown that the time scale for adsorption is much greater than gas-phase residence times. Adsorbed compounds significantly alter the reactor composition, particularly at the initiation of each pulse. As a consequence careful attention must be paid to reactor design and operation in order to control deposition rates and maintain quality.