Improvement in adhesion and decrease in stress of MgO thin films due to vapour chopping

Abstract

We report the enhancement of adhesion and reduction of stress of MgO thin films by using vapour chopping technique. Vapour chopped (VC) and nonchopped (NC) magnesium oxide thin films (thickness ∼ 600 nm) have been prepared by thermal oxidation (in air) of vacuum evaporated magnesium films. The effect of oxidation temperature of 573, 623 and 673 K and duration 90 and 180 min on the adhesion and intrinsic stress of MgO thin films due to vapour chopping were studied. Adhesion and stress was investigated by direct pull off method and interferometric method respectively. Adhesion was in the range 27–54.8 × 10 4 N/m 2 for vapour chopped thin films, as compared to 20.1–41.9 × 10 4 N/m 2 of nonchopped MgO thin films. Intrinsic stress was found to decrease from 70.07 to 22.86 × 10 7 N/m 2 for nonchopped and to 45.63 to 11.83 × 10 7 N/m 2 for vapour chopped MgO thin films.