Candidate
Shuo Zheng
Title
Fabrication of AFM tips with a capability of direct positioning upon samples
Supervisor
Bo Cui
Abstract
Atomic Force Microscope (AFM) is a versatile tool which is used in many areas within nano technology. As the successor of scanning tunneling microscope (STM), AFM is a combination of the principles of STM and the stylus profilometer (SP). In order to meet the requirements for different applications, AFM tips have various shapes. In our case, we fabricate the tip with the shape that is feasible for direct positioning upon sample surfaces.
The logic behind our process is to protect the region of wanted and then remove the unprotected areas so that the desired shape can be released. Therefore, our process includes three major steps. First we implement angled-deposition to deposit the protective metal, which is Al in our case, onto some commercial tips. Some regions remain uncovered because angled-deposited Al cannot reach these regions. Then the Si at unprotected areas will be removed by Deep Si RIE. At last, we can get the product after removal of protective metal. This simple process is able to perform on tips with any shapes and redefine their shapes so that the capability of direct positioning upon samples is available.