Hardness determination at nanoscale by ultrasonic vibration-assisted AFM

Mechanical properties at nanoscale are crucial fators in the applications such as nanoscale interconnects and active components in electronic, optoelectronic, and electromechanical devices. Determination of the hardness of nanostructures, especially nano-thin-film, with regime from several to hundreds nanometers is a challenge. In this study, we proposed an ultrasonic vibration (USV)-assisted atomic force microscopy (AFM) method to measure the hardness of bulk materials and nano-thin-film with the thickness of 25 and hundreds nanometers. The hardness properties of material can be detected by the cantilever phase response in the USV machining process. By recording the depth-phase data, the hardness information can be extracted through fitting the data by the mathematical model. The theoretical analysis and experimental results valid the proposed method