ES 240 Project: Finite Element Modeling of Nano- Indentation of Thin Film Materials

1. Introduction to Nanoindentation Process 2. Model Description 3. Model Validation 4. Results and Discussion 5. Effect of Substrates 6. Conclusion and Future Work Outline

Displacement Sensor Force Sensor Film Substrate Indenter 1. Introduction to Nanoindentation Process

100 nm 1000 nm 900 nm Indenter: Diamond Film: Copper Substrate: 1. Copper 2. Sapphire 3. Silicon 4. Glass 5. Polymer 2. Model Description -Dimensions and Materials of The Model

Elastic Materials E (GPa) v (-) Diamond Sapphire Silicon Glass730.3 Polymer300.3 Elastic/Plastic Mateirial E (GPa) V(-)Y (GPa) Plastic Constitutive Copper Model Description -Materials Properties

Indenter Film Substrate Element Type: 4-Noded Axisymmetric Element Size (Edge length): ~2 nm (Indentation region) ~10 nm (Other region) Mesh Sensitivity: Refined-mesh model gives similar results. 2. Model Description -Mesh and Element

Experimental : Theoretical: : Reduced Modulus : Film’s E and v : Indenter’s E and v : Indenter and film’s contact area 3. Model Validation -Reduced Modulus (copper substrate)

Simulated: Theoretical: 3. Model Validation -Theoretical and Simulated Results (copper substrate)

4. Model Results - Mises Stress (copper substrate)

4. Model Results - Effective Plastic Strain (copper substrate)

Model’s Prediction Experimental Results (W, Nix et al, Acta Materialia, 50, 23, 2002) 5. Effect of Substrates - Load vs. Displacement

Model’s Prediction Experimental Results (W, Nix et al, Acta Materialia, 50, 23, 2002) 5. Effect of Substrates - Reduced Modulus

5. Effect of Substrates - Deflection of Substrate

1. Nanoindentation process can be simulated using finite element method. 2. The reduced modulus predicted by the finite- element model is very close to analytical results. 3. Stiff substrate tends to overestimate thin film’s modulus, and compliant substrate tends to underestimate thin film’s modulus. 5. Conclusion