Date of Award

Spring 1996

Document Type

Thesis

Degree Name

Master of Science in Engineering Science- (M.S.)

Department

Committee for the Interdisciplinary Program in Materials Science and Engineering

First Advisor

Roland A. Levy

Second Advisor

Lev N. Krasnoperov

Third Advisor

N. M. Ravindra

Abstract

This study focuses on PECVD to make tungsten film for X-ray absorber for use in X-ray lithography applications. The previous LPCVD study was used for comparison of film properties. A cold wall, single wafer, Spectrum 211 CVD reactor was used for the deposition of tungsten from H2 and WF6. The growth kinetics were determined as a function of temperature, pressure and flow rate ratio. The deposition rate was found to follow an Arrehnius behavior between 300-500°C with an activation energy of 55.7 kJ/mol. The growth rate increased linearly with total pressure and H2 partial pressure. In the H2/WF6 ratio studies growth rate increased up to flow ratio of 10 followed by saturation. The as-deposited film stress is strongly dependent on deposition temperature with a weak relationship with pressure and flow ratio. The resistivity showed no . parameter dependency, with the films having preferred orientation of the (200) plane. Plasma enhanced CVD was used for the deposition of tungsten film from the same precursors and the same Spectrum 211 CVD reactor under the same deposition parameter range used in the LPCVD study for temperature, pressure, and WF6 and H.2 flow rates, RF plasma power was varied. Zero stress was achieved at RF power of 400W, 600°C, 500 mTorr, WF6 and H2 flow rates at 5 and 100 sccm respectively. In addition, resistivity values were as low or lower than those reported in the LPCVD study.

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