Improvement Of AFM.IPC-208B System And Its Piezoelectric Cantilever Research

Since 21st century, Scanning Probe Microscopes (SPM) has become an indispensable research instrument in nano-testing and processing. In particular, the Atomic Force Microscope (AFM) with its atomic level accuracy (0.1nm) has been widely used in materials science, bio-medicine, nano-electromechanical and Nano/Micro process areas. With the rapid development of nano-technology and in-depth applications in the field of nano-inspection and processing, atomic force microscope technology itself has also got a great development. Chongqing University Heng-Rui Nano-technical workstation try to optimize the system performance and expand its applications on IPC-208B type atomic force microscope, and be committed to research and development of multi-mode atomic force microscope. In this paper, funded by the Natural Science Fund project of Chongqing Science and Technology Commission and Chongqing University Natural Science Youth Fund project, I carried out some study such as system performance improvements of IPC-208B type atomic force microscope, the latest experimental applications and piezoelectric micro-cantilever research. So, my main researches in the following areas:①Systematic study was carried out on the SPM for AFM-based with working principle, the development and applications, discussed in the theory of piezoelectric micro-cantilever applications and development at home and abroad in detail, with emphasis on the current study of the piezoelectric micro-cantilever applied in AFM system.②Recent laboratory works were introduced about the IPC-208B type atomic force microscope system improvement and its latest new application experiments. I introduced AFM.IPC-208B-type system components, with emphasis on the lens body with stepper motor, piezoelectric ceramics, micro-cantilever and transmission system. For the improvements on the AFM system equipped with a regulating device for AFM micro-cantilever, which gives attention to STM and AFM, as well as the added conditioning monitoring devices for cantilever - probe, in order to enhance the accuracy of the adjustment, I improve the adjustment efficiency and avoid the firing pin from happening, all this aims to improve the operability of micro-cantilever. I chose a piezoelectric scanner to complete the under scanning setting, so that the scanning range expanded from the original 1000×1000 nm2 to 10×10μm2, achieving a wide scanning range. Detail the latest system applications were shown in micro-processing, bio-medical samples characterization, ferromagnetic and ferroelectric materials, fiber material characterization and polymer characterization.③Piezoelectric micro-cantilever was designed for AFM system. According to the relation betwween micro-cantilever deformation and its displacement, based on the AFM piezoelectric micro-cantilever design principle and the selected work mode principle, I gave the complete piezoelectric micro-cantilever structure (Si + pole + piezoelectric film+ pole) and system design; analyzed and compared characteristics of the PZT and ZnO piezoelectric materials, and analyzed the two kinds work ways of piezoelectric micro-cantilever sensors and implementation; analyzed the preparation of micro-cantilever and probe; analyzed characteristics of piezoelectric micro-cantilever based on the comparison between micro-cantilever and other methods, in the end, I analyzed the application prospect of piezoelectric micro-cantilever in the AFM .④Finite element analysis and ANSYS simulation for the AFM piezoelectric micro-cantilever were completed. According to finite element and ANSYS simulation principle, in accordance with atomic force microscope working environment and requirements, I used the finite element method to establish micro-cantilever model, and used ANSYS software to analyze the model and obtained results of the piezoelectric analysis solution: change relationship of voltage with the force or displacement. I analyzed the impact on the voltage of the various model parameters: length, width, thickness and so on, received three first order modal vibration maps and natural frequency modal analysis results, and discussed the different size parameters on the modal frequency of the impact; and I analyzed impact of different probe needle position on the of modal frequency and sensitivity, and made performance comparison analysis whether consider the extending side; using voltage/displacement (△U/△D) the model sensitivity scale, I analyzed the impact of the size parameters on the sensitivity. At last by optimization analysis, the simulation results was shown: when cantilever length is 200μm and its width is 50μm, extended length is 20μm and its width is10μm, piezoelectric film thickness is1μm, Si thickness is 1.5μm, pole thickness is 0.2μm, we got the basal frequency f=44.972kHz, the sensitivity K=1.71mv/nm. According to the of AFM probe wave 0—100 nm,the piezoelectric signal is about 0—171 mv,which is convenient to be identified for AFM system.