Deep-trench RIE optimization for high performance MEMS microsensors

Aydemir, Akın
This thesis presents the optimization of deep reactive ion etching process (DRIE) to achieve high precision 3-dimensional integrated micro electro mechanical systems (MEMS) sensors with high aspect ratio structures. Two optimization processes have been performed to achieve 20 μm depth for 1 μm opening for a dissolved wafer process (DWP) and to achieve 100 μm depth for 1 μm opening for silicon-on-glass (SOG) process. A number of parameters affecting the etch rate and profile angle are investigated, including the step times, etch step pressure, platen power, and electrode temperature. Silicon etch samples are prepared and processed in METU-MET facilities to understand and optimize the DRIE process parameters that can be used for the production of MEMS gyroscopes and accelerometers. The etch samples for DWP are masked using a photoresist, Shipley S1813. After the optimization process, vertical trench profiles are achieved with minimum critical dimension loss for trench depths up to 20 μm. Since the selectivity of the resist is not sufficient for 100 μm deep trench etch process, silicon dioxide (SiO2) is used as the mask for this process. At the end of the optimization processes, more than 100 μm depth for 1 μm opening with almost vertical sidewalls are achieved. In summary, this study provides an extensive understanding of the DRIE process for successful implementations of integrated MEMS sensors.


Mems gyroscopes for tactical-grade inertial measurement applications
Alper, Said Emre; Akın, Tayfun; Department of Electrical and Electronics Engineering (2005)
This thesis reports the development of high-performance symmetric and decoupled micromachined gyroscopes for tactical-grade inertial measurement applications. The symmetric structure allows easy matching of the resonance frequencies of the drive and sense modes of the gyroscopes for achieving high angular rate sensitivity; while the decoupled drive and sense modes minimizes mechanical cross-coupling for low-noise and stable operation. Three different and new symmetric and decoupled gyroscope structures with...
Development of atomic force microscopy system and kelvin probe microscopy system for use in semiconductor nanocrystal characterization
Bostancı, Umut; Turan, Raşit; Department of Physics (2007)
Atomic Force Microscopy (AFM) and Kelvin Probe Microscopy (KPM) are two surface characterization methods suitable for semiconductor nanocrystal applications. In this thesis work, an AFM system with KPM capability was developed and implemented. It was observed that, the effect of electrostatic interaction of the probe cantilever with the sample can be significantly reduced by using higher order resonant modes for Kelvin force detection. Germanium nanocrystals were grown on silicon substrate using different g...
Development of software for calculations of the reflectance, transmittance and absorptance of multilayered thin films
Şimşek, Yusuf; Esendemir, Akif; Department of Physics (2008)
The aim of this study is to develop a software which calculates reflection, transmission and absorption of multilayered thin films by using complex indices of refraction, as a function of both wavelength and thickness. For these calculations matrix methods will be considered and this software is programmed with the matrix method. Outputs of the program will be compared with the theoretical and experimental results studied in the scientific papers.
Dynamic ion behavior in plasma source ion implantation
Bozkurt, Bilge; Bilikmen, Kadri Sinan; Department of Physics (2006)
The aim of this work is to analytically treat the dynamic ion behavior during the evolution of the ion matrix sheath, considering the industrial application plasma source ion implantation for both planar and cylindrical targets, and then to de-velop a code that simulates this dynamic ion behavior numerically. If the sepa-ration between the electrodes in a discharge tube is small, upon the application of a large potential between the electrodes, an ion matrix sheath is formed, which fills the whole inter-ele...
Structural, electrical and optical characterization of ge-implanted gase single crystal grown by Bridgman Method
Karaağaç, Hazbullah; Akınoğlu, Bülent Gültekin; Department of Physics (2005)
In this work, structural, electrical and optical characterization of as-grown, Ge-implanted, and annealed GaSe single crystals grown by using 3-zone vertical Bridgman-Stockbarger system, have been studied by carrying out X-ray Diffraction (XRD), electrical conductivity, Hall effect, photoconductivity, and spectral transmission measurements. The temperature dependent electrical conductivity of these samples have been measured between 100 and 400 K. As a result, it was observed that upon implanting GaSe with ...
Citation Formats
A. Aydemir, “Deep-trench RIE optimization for high performance MEMS microsensors,” M.S. - Master of Science, Middle East Technical University, 2007.