Influence of the sputtering glancing angle on the microstructure and adsorption characteristics of Zr-Co-RE getter films

Abstract

Zr-Co-RE non-evaporable getter films have excellent gas adsorption performance therefore can be used in vacuum sealed electronic devices. The microstructure of getter films has vital effect on adsorption performance. In this paper, Zr-Co-RE films deposited by DC magnetron sputtering at different glancing angles are investigated including microstructures and adsorption characteristics. The surface and cross-sectional morphologies demonstrate loose, porous and columnar-like structure which forms because of low lateral mobility of Zr and Co atoms and shadowing effect of non-perpendicular sputtering. Zr-Co-RE films are amorphous or nanocrystalline structure. The films deposited at 90° glancing angle show large grain size. After Zr-Co-RE films are heated at 350 °C for 15 min, the H2 adsorption capacity and pumping speed at ambient temperature are tested. The films grown at 90° glancing angle have highest initial pumping speed (103.9 ml s−1 cm−2), which owe to its more gas diffusion path and active surface, meanwhile, the adsorption capacity is lower than 60° because of difficult and limited diffusion process into getter matrix. The films grown at 60° glancing angle have best adsorption capacity (71.5 Pa.ml cm−2) and pumping speed stability.