Observation of the Structure of Tungsten Films Prepared by MOCVD

The tungsten films with ultra microstructure on CuCrZr alloy and China Low Acti- vation Martensitic (CLAM) steel have been prepared by metal organic chemical vapor deposition (MOCVD). The films were produced by pyrolysing the tungsten hexacarbonyl at air or argon atmosphere. When formed at or below 400 ^? C, they were poorly crystalized and the films showed low quality in thickness, density, bonding performance etc. While above this temperature, the properties of tungsten films have been improved, all the films consist of tungsten in the β-W. And β-W can change into α-W after heat treatment. As in other variations of pyrolysis, oxy- gen and carbon were observed. When filled with argon, the oxygen and carbon content would reduce apparently. Tungsten films prepared by MOCVD have stable chemical composition and microstructure. Besides, the properties of films on CuCrZr alloy are better than that on CLAM steel.