Nanoscaled thin films are typically deposited on various substrates to achieve their unique characteristics. These thin film systems can be affected by the thickness variations between the thin film and the accompanying substrate. To investigate the thickness dependence of a nanoscaled thin film system, ultrasonic atomic force microscopy (Ultrasonic-AFM) which can evaluate the localized elastic modulus using the contact resonance frequency of a vibrating cantilever is applied. Copper thin films of low elastic modulus were deposited on silicon substrates of high elastic modulus. By contrast, Si₃N₄ and Ti thin films of high elastic modulus were deposited on GaAs and glass substrates of low elastic modulus, respectively. Experimental results showed that the thin films with different thickness were affected significantly by the substrate and the contact resonance frequency changes as a result of the varying thickness of the thin films. This research demonstrate that Ultrasonic-AFM may be a novel technique for the nondestructive measurement of nanoscale thin film thickness by considering substrate features.

通常将纳米级薄膜沉积在各种基底上以实现其独特的特性。这些薄膜系统可能会受到薄膜与所附基板之间厚度变化的影响。为了研究纳米级薄膜系统的厚度依赖性，应用了超声原子力显微镜（Ultrasonic-AFM），该技术可以利用振动悬臂的接触共振频率来评估局部弹性模量。将低弹性模量的铜薄膜沉积在高弹性模量的硅基板上。相比之下，Si ₃ N ₄高弹性模量的Ti和Ti薄膜分别沉积在GaAs和低弹性模量的玻璃基板上。实验结果表明，不同厚度的薄膜受到衬底的影响很大，并且由于薄膜厚度的变化，接触共振频率也发生了变化。这项研究表明，超声AFM可能是一种通过考虑衬底特征来无损测量纳米级薄膜厚度的新技术。