Development of high performance active materials for microbolometers

Download
index.pdf
2011
Eroğlu, Numan
Show full item record
268
views
207
downloads
This thesis reports the development of Vanadium Tungsten Oxide (VWO) film as an active detector material for uncooled infrared detectors by using the reactive DC magnetron co-sputtering method. VWO is a doped form of the Vanadium Oxide (VOx) which is known as a prominent material for uncooled infrared detectors with its high TCR, low resistivity, and low noise properties. VOx is a widely preferred material for commercialized uncooled infrared detectors along with its drawbacks. Fabrication is fairly difficult due to its unstable material properties and the need for low process temperatures for a monolithic, CMOS compatible surface micromachining process. Hence, a new material with high performance and easier fabrication is needed. This thesis is the first study at METU on the development of high-performance VWO as an active detector material for uncooled infrared detectors. Deposition studies of VWO primarily started by measuring the effects of deposition parameters upon the magnetron sputtering system. Because the high effectiveness of the tungsten doping has been obtained for the doping level below 10% according to literary information, maximum vanadium (V) deposition rate together with minimum tungsten (W) deposition rate has been initially aimed. TCR of the VWO films has been measured between -2.48 %/K and -3.31 %/K, and the variation of noise corner frequency from 0.6 kHz to 8 kHz has been observed. In addition to these results of VWO, a favorable VOx recipe which has the highest performance done at METU in terms of resistance, TCR, noise and uniformity has also attained during the studies. Structural characterization of VWO is achieved using XPS, XRD, and AFM characterization techniques. Other than the sputtering parameters, post-annealing process and oxygen plasma exposure was examined as well. A general observation of the post-annealing is that it decreases not merely the TCR but also the noise of the deposited film. A short-period oxygen plasma exposure has a constructive effect on the noise behavior. Fabricated vanadium tungsten oxide with sandwich type resistor structure shows very close but better bolometric properties when compared with the yttrium barium copper oxide (YBCO), which is another material being studied in scope of other theses at METU. XPS, XRD and AFM characterization methods have been used for the structural characterization of vanadium-tungsten-oxide.
Tungsten., Thin films., Nanoelectromechanical systems.
http://etd.lib.metu.edu.tr/upload/12613533/index.pdf
https://hdl.handle.net/11511/20984
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Production of hydrogenated nanocrystalline silicon based thin film transistor
Aliyeva, Tamila; Atılgan, İsmail; Department of Physics (2010)
The instability under bias voltage stress and low mobility of hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT), produced by plasma enhanced chemical vapor deposition (PECVD) technique, are the main problems impeding the implementation of active matrix arrays for light emitting diode display panels and their peripheral circuitry. Replacing a-Si:H by hydrogenated nanocrystalline silicon film (nc-Si:H) seems a solution due to its higher mobility and better stability. Therefore nc-Si:H TFT was...
Investigation of material properties of magnetron sputtered CuAg-In-Se thin films
Güllü, Hasan Hüseyin; Parlak, Mehmet (null; 2016-09-23)
Thin films of copper based chalcopyrite absorber materials are attracting the attention of many researchers because of their favorable optoelectronic properties and good stability makes them suitable for photovoltaic and optoelectronic device applications. These compounds are particularly suitable for making p-n hetero-junctions with the II-VI compounds. Therefore, the utilization of I-III-VI2 group of chalcopyrite semiconductors has been reported in the literature for application in thin film solar cells. ...
Investigation Of The Device Properties Of Cztse Thin Films For Solar Cells
Bayraklı, Özge; Güllü, Hasan Hüseyin; Parlak, Mehmet (2016-10-02)
Thin Film Solar Cell has received a considerable attention in the photovoltaic industry. While the efficiency of thin film amorphous silicon is about %14, the efficiency of Cu(In,Ga)Se2 (CIGS) thin film based solar cells ,is very popular in the recent year, reached the value of %20. But CIGS based solar cells have some constraints such as its extensive and large scale production in terms of availability of its constituent elements. On the other hand, Kesterit based solar cells such as Cu2ZnSnSe4 (CZTSe) hav...
Development of high performance uncooled infrared detector materials
Kebapçı, Başak; Akın, Tayfun; Turan, Raşit; Department of Micro and Nanotechnology (2011)
This thesis reports both the optimizations of the vanadium oxide (VOx) thin film as an active infrared detector material by the magnetron sputtering deposition method and its use during fabrication of proper resistors for the microbolometers. Vanadium oxide is a preferred material for microbolometers, as it provides high TCR value, low noise, and reasonable resistance, and a number of high-tech companies have used this material to obtain state-of-the-art microbolometer arrays. This material is first used in...
Efficient Light Trapping in Inverted Nanopyramid Thin Crystalline Silicon Membranes for Solar Cell Applications
MAVROKEFALOS, Anastassios; HAN, Sang Eon; Yerci, Selçuk; Branham, Matthew S.; CHEN, Gang (2012-06-01)
Thin-film crystalline silicon (c-Si) solar cells with light-trapping structures can enhance light absorption within the semiconductor absorber layer and reduce material usage. Here we demonstrate that an inverted nanopyramid light-trapping scheme for c-Si thin films, fabricated at wafer scale via a low-cost wet etching process, significantly enhances absorption within the c-Si layer. A broadband enhancement in absorptance that approaches the Yablo-novitch limit (Yablo-novitch, E. J. Opt. Soc. Am. 1987, 72, ...
Citation Formats
N. Eroğlu, “Development of high performance active materials for microbolometers,” M.S. - Master of Science, Middle East Technical University, 2011.
METU IIS - Integrated Information Service open@metu.edu.tr