Atomic Force Microscopy Indentation of Fluorocarbon Thin Films Fabricated by Plasma Enhanced Chemical Deposition at Low Radio Frequency Power

Abstract

Atomic force microscopy (AFM) indentation technique is used for characterization of mechanical properties of fluorocarbon (CFx) thin films obtained from C4F8 gas by plasma enhanced chemical vapour deposition at low r.f. power (5¿30 W) and d.c. bias potential (10¿80 V). This particular deposition method renders films with good hydrophobic property and high plastic compliance. Commercially available AFMprobeswith stiff cantilevers (10¿ 20 N/m) and silicon sharpened tips (tip radius b10 nm) are used for indentations and imaging of the resulted indentation imprints. Force depth curves and imprint characteristics are used for determination of film hardness, elasticity modulus and plasticity index. Themeasurements showthat the decrease of the discharge power results in deposition of films with decreased hardness and stiffness and increased plasticity index. Nanolithography based on AFM indentation is demonstrated on thin films (thickness of 40 nm) with good plastic compliance.