- Title
- MEMS-based nanopositioning for on-chip high-speed scanning probe microscopy
- Creator
- Maroufi, Mohammad
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2015
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Nanopositioners constitute a crucial component of numerous emerging scientific instruments due to their ability to produce displacements with nanometer or sub-nanometer precision. In particular, these devices are predominantly used in scanning probe microscopes (SPMs) to position samples beneath the probe. The positioning precision of an incorporated nanopositioner directly affects the imaging quality of these microscopes. Since SPMs are mechanical microscopes, their imaging frame rate also depends on the speed of the implemented nanopositioner. In this research, the micro electromechanical system (MEMS) technology, as an alternative to macroscale technology, is used to realize high-speed on-chip nanopositioners for SPMs. Atomic force microscopes (AFMs), as an important subset of SPMs, are also used to test the capability of these nanopositioners in imaging. A comprehensive study is conducted on previously reported MEMS nanopositioners proposed for different applications. Various actuation and sensing techniques, which are viable to be incorporated in MEMS nanopositioners, are presented and their characteristics are thoroughly discussed. The design concerns relevant to electrostatic MEMS nanopositioners are discussed using analytical models. These models are later used as the baseline for designing novel electrostatic MEMS nanopositioners. These nanopositioners are fabricated and fully characterized as explained in different chapters in this thesis. All proposed nanopositioners are also used within an AFM for imaging. In addition, closed-loop feedback controllers are implemented for a number of the nanopositioners to attain raster and non-raster scans with a superior tracking performance. Both serial and parallel kinematic mechanisms are attempted for the implementation of the proposed nanopositioners. Various performance parameters relevant to the use of either of these mechanisms are investigated using experimental results. Displacement sensing bandwidth in some of the proposed nanopositioners is identified as a restricting factor to achieve higher scanning speeds. Hence, a novel high-bandwidth on-chip sensing mechanism for measuring stage displacement is introduced. The sensor is implemented in a single-degree-of-freedom MEMS nanopositioner as a test bench. Both analytical models and experimental data are provided for the sensor to investigate its static and dynamic features. To achieve a wider bandwidth, the on-chip configuration of the sensor is also modified, and the modified version is implemented in a novel two-degree-of-freedom MEMS nanopositioner. The performance results obtained from the proposed nanopositioners highlight their potential utility in a miniaturized high-speed AFM. The proposed nanopositioners demonstrate outstanding characteristics in terms of bandwidth, cross coupling rejection, and displacement range. All designs have the potential to be used in high accuracy positioning applications, particularly in on-chip AFMs.
- Subject
- nanopositioner; MEMS; atomic force microscope
- Identifier
- http://hdl.handle.net/1959.13/1309594
- Identifier
- uon:21911
- Rights
- Copyright 2015 Mohammad Maroufi
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Abstract | 172 KB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Thesis | 16 MB | Adobe Acrobat PDF | View Details Download |