| Nano-technology has become the world trend of science and technology development, which has greatly promoted the advancement of modern science and technology, industrial production, human society and so on. Micro-nano detection technology is not only an important nano-technology, but also the basis of it. Along with the advancement of technology, it develops many new theories, new methods and new technologies about micro-nano detection technology. Scanning tunneling microscope (STM) and atomic force microscope (AFM) are not only the milestone of micro-nano detection technology development in the history, but also the basis for the development of nano-technology and essential research tools for nano-scientists and engineers. Compared to STM, AFM has been the more demanded and applied tools for researchers to pursue more ambitious goals. In the large scanning scale, because the piezoelectric scanner has cross-coupling error between direction X (or Y) and direction Z, the sample image detected by the traditional AFM is warped and distorted, which can only be corrected by software. The disadvantage of traditional AFM limits the increment of scanning area. In this situation, the paper proposes an AFM system based on new scanner, which solve the problem of cross-coupling error very well.In this project, I have worked on theoretical methods, systems design and experiment aspects of the AFM system, the main research work and innovation as follows:1. This thesis proposes a new method of AFM based on a plat scanner. The advantage of this method is using the plate scanner to scan the sample and using the feedback controller of direction Z to drive the up and down feedback movement of micro cantilever. The method realizes the separation of XY plane and direction Z, which removes the cross-coupling error. So the new method can ensure the performance of getting the ideal image by AFM system in wide range scanning.2. Based on the above principles and new methods, we have developed the AFM system based on the plat scanner, which has superior performances. Firstly, we developed the AFM probe based on the plat scanner successfully including the novel plat scanner, the unique Z-direction feedback controller and micro linear drive with the coarse-tuning and fine-tuning. Secondly, we designed the optical path of detection, developed the plate scanning drive circuit with excellent performances, the PSD pre-amplifier circuit and the PID feedback circuit of Z-direction feedback controller. We use the AD/DA cards with high-speed and high-precision to achieve the data's input and output and conversion of the control signals. In addition, the plat scanning drive controller and the image analysis software with good performances are developed independently.3. In the AFM system based on the plat scanner, firstly we introduced the CCD microscope and camera monitoring system, which help to realize real-time monitoring to the operation between the probe and the samples and the probe scanning effectively. Then, we build the micro-dynamic platform in XY directions, which help to realize the performances of good scan orientation to any region and a wild range scanning based the sequence image scanning and image mosaic technology.4. We give the error analysis of the AFM system based on plat scanner and present the optimization scheme, which is certified to further enhance and improve the system's performances. And we carry on a large number of experimental tests. Firstly, though some experimental results we contrast the AFM system based on the plat scanners to traditional scanners. We perform the scanning image experiments to the silver-plating film, the organic materials CuPc and the Ge quantum point. We also research the film process to gold-plating. The experiments show that the AFM system based on plat scanner has many advantages of good image contrast and definition even in a large scanning range, and has a universal application with good scanning stability and repeatability. |
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