International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology, Changchun, China.
College of Medical Engineering, Jilin Medical University, Jilin, China.
J Microsc. 2022 Sep;287(3):148-155. doi: 10.1111/jmi.13129. Epub 2022 Jul 23.
The phase image of tapping-mode atomic force microscopy (TM-AFM) contains energy dissipation, which is related to the sample information on the physical properties such as the sample Young's modulus, adhesion, surface morphology and subsurface morphology. When TM-AFM is used for sample measurement, the frequency near the first resonance peak of probe is usually selected to drive the probe vibration. When the probe vibration is driven by the frequency, the probe has a high amplitude sensitivity, but the phase sensitivity is relatively low. In this paper, the frequency at the probe phase resonance peak was selected for driving the probe vibration to measure the sample, which improved the image resolution. Phase imaging was performed on three uniform photoresist samples with different thicknesses and the same structure. When the scanning parameters were fixed and the probe setpoint value was changed alone, it was found that with the decrease of setpoint value the horizontal resolution of the phase subsurface image was decreased, and the depth sensitivity was increased first and then decreased. The result shows that TM-AFM working at the phase resonance peak can better realise the subsurface imaging of samples at different depths. Phase subsurface imaging at the resonance can be used to quantitatively obtain subsurface phase images of different depths.
敲击模式原子力显微镜（TM-AFM）的相图包含能量耗散，这与样品的物理性质信息有关，例如样品杨氏模量、附着力、表面形貌和亚表面形貌。当 TM-AFM 用于样品测量时，通常选择探针的第一个共振峰附近的频率来驱动探针振动。当探针以该频率驱动振动时，探针具有高的振幅灵敏度，但相位灵敏度相对较低。本文选择探针相位共振峰的频率来驱动探针振动以测量样品，从而提高了图像分辨率。对三个具有不同厚度和相同结构的均匀光刻胶样品进行了相成像。当扫描参数固定且仅单独改变探针设定值时，发现随着设定值的降低，相亚表面图像的水平分辨率降低，深度灵敏度先增加后减小。结果表明，在相共振点工作的 TM-AFM 可以更好地实现不同深度的样品亚表面成像。在共振时的相亚表面成像可用于定量获得不同深度的亚表面相位图像。
