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原子力显微术(AFM)是近年来新发展的一种高清晰度的显微技术,它能显示出物体表面附近的势能分布,并根据这种分布,可以直接描绘出物体表面的形貌.在一定的工作方式下,AFM可以分辨出导体或者绝缘体表面的单个原子.组成AFM的关键部分是一个有弹性的力传感器探头,它应包括如下一些特性:一个很锐的尖端、低的力常数和高的机械谐振频率.这些可以利用微加工技术、使用新型方法和缩小探头的尺寸来达到目的.以下所列的都是一些能获得理想的AFM探头特性的微加工工艺.这些加工工艺(1)制造不带尖头的sio_2或si_3N_4薄膜悬臂梁,(2)通过在si(100)衬底上腐蚀出铸坑,制造带有集成的金字塔尖端的si_3n_4悬臂梁.(3)利用各向同性腐蚀和各向异性的等离子刻蚀,制造带有锥形尖的sio_2悬臂梁,(4)利用各向异性腐蚀,制造带正四面体尖头的sio_2悬臂梁.每一种工艺都利用(100)晶向的硅片作为衬底并且依靠常规的半导体制造工艺.利用上述的方法制造出来的尖头的质量可以达到或超出用于AFM或STM中的常规探头.另外可选择制造尖头的方法是通过孔洞蒸发材料或者利用有选择的CVD淀积使W金属进入一个锥形腐蚀抗.但这些方法都还未能成功地用于制造悬臂梁.
Atomic force microscopy (AFM) is a newly developed high-resolution microscopy technique developed in recent years. It displays the distribution of potential energy near the surface of an object and can directly depict the surface morphology of the object according to this distribution. Under certain operating conditions, the AFM can discern a single atom on the surface of a conductor or insulator The key component of an AFM is a flexible force transducer probe that includes the following features: a sharp tip, low force constant And high mechanical resonance frequencies, these can be achieved using micromachining techniques, using new methods and reducing the size of the probe.The following are some of the micromachining processes that achieve the desired AFM probe characteristics.These processes (1 ) Fabrication of thin film cantilevered sio_2 or si_3N_4 cantilevers, (2) fabrication of si_3n_4 cantilever with integrated pyramid tip by etching pits on a si (100) substrate. (3) Corrosion and anisotropic plasma etching to fabricate sio_2 cantilever with tapered tips, (4) anisotropic etching to fabricate sio_2 cantilever with tetrahedron tips, each of which utilizes (100 Crystal orientation Of the silicon substrate as a substrate and rely on conventional semiconductor manufacturing processes.The quality of the tips produced using the above method can reach or exceed the conventional ones used in AFM or STM.Alternatively, Evaporation of the material or the use of selective CVD deposition causes the W metal to enter a tapered corrosion resistance, but none of these methods have been successfully used to fabricate cantilever beams.