Study on the delamination of tungsten thin films on Sb₂Te₃

To investigate the reliability of electrode materials for chalcogenide random access memory (C-RAM) applications, the geometry and time evolution of the worm-like delamination patterns on a tungsten/Sb_2Te_3 bilayer system surface are observed by field emission scanning electronic microscope (FESEM) and optical microscopy. The tungsten film stress and interface toughness are estimated using a straight-side model. After confirming the instability of this system being due to large compressive stress stored in the tungsten film and relative poor interface adhesion, a preliminary solution as the inset of a TiN adhesion layer is presented to improve the system performances.