Nanoindentation and Adhesion Properties of Ta Thin Films

Abstract EN

Ta films were sputtered onto a glass substrate with thicknesses from 500 Å to 1500 Å under the following conditions: (a) as-deposited films were maintained at room temperature (RT), (b) films were postannealed at TA=150°C for 1 h, and (c) films were postannealed at TA=250°C for 1 h.

X-ray diffraction (XRD) results revealed that the Ta films had a body-centered cubic (BCC) structure.

Postannealing conditions and thicker Ta films exhibited a stronger Ta (110) crystallization than as-deposited and thinner films.

The nanoindention results revealed that Ta thin films are sensitive to mean grain size, including a valuable hardness (H) and Young’s modulus (E).

High nanomechanical properties of as-deposited and thinner films can be investigated by grain refinement, which is consistent with the Hall-Petch effect.

The surface energy of as-deposited Ta films was higher than that in postannealing treatments.

The adhesion of as-deposited Ta films was stronger than postannealing treatments because of crystalline degree effect.

The maximal H and E and the optimal adhesion of an as-deposited 500-Å-thick Ta film were 15.6 GPa, 180 GPa, and 51.56 mJ/mm2, respectively, suggesting that a 500-Å-thick Ta thin film can be used in seed and protective layer applications.