The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Low pressure chemical vapor deposition of tungsten as an absorber for x-ray masks
Author:	Chen, Hongyu
View Online:	njit-etd1995-073 (xii, 61 pages ~ 2.1 MB pdf)
Department:	Committee for the Interdisciplinary Program in Materials Science and Engineering
Degree:	Master of Science
Program:	Engineering Science
Document Type:	Thesis
Advisory Committee:	Levy, Roland A. (Committee chair) Grow, James M. (Committee member) Krasnoperov, Lev N. (Committee member)
Date:	1995-10
Keywords:	Chemical vapor deposition. Tungsten films. Low pressure chemical vapor deposition.
Availability:	Unrestricted
Abstract:	Tungsten film is one of promising materials for X-ray absorber in X-ray Lithography technology because of its high X-ray absorption and refractory properties. This study focus on CVD method to make tungsten film for X-ray absorber. In this work, a cold wall, single wafer, Spectrum 211 CVD reactor was used for the deposition of tungsten from H, and WF6. The growth kinetics were determined as a function of temperature, pressure and flow ratio. The deposition rate of as deposited tungsten films was found to follow an Arrehnius behavior in the range of 300-500°C with an activation energy of 55.7 kJ/mol. The growth rate was seen to increase linearly with total pressure and H, partial pressure. In the H2/WF6 ratio studies conducted at 500°C and 500mTorr, growth rate increase with flow ratio when lower than 10 followed by saturation above this ratio. The stress of as deposited film strongly dependent on deposition temperature and has weak relationship with pressure and flow ratio. The `buried layer model' can explain the stress of as deposited film very well. The resistivity of the film is no relationship with pressure, flow ratio and dependent on temperature. The deposited films have preferred orientation of the (200) plane.