METU MEMS Research and Applications Center (METU-MEMS)

MEMS activities at METU have been continuing since 1995 in the framework of a number of national/international projects, including NATO-SfS (TU-MICROSYSTEMS), US NSF, COST, FP6 (AMICOM), and several national projects. During these projects, a wide variety of sensors and devices have been developed, such as pressure sensors, CMOS infrared detectors, accelerometers, gyroscopes, humidity sensors, temperature sensors, frost sensors, biosensors, energy harvesters, and various RF MEMS componentsIn 1998, METU took over a 35 Million Euros invested IC fabrication facility from the government, and this facility has been converted to METU-MEMS Center. The infrastructure of the facility has been upgraded substantially with national funds totaling over 20 Million Euros, and the facility allows 4”, 6”, and partially 8” wafer processing. However, there is still need for funding to hire more researchers and train them in this high-tech field, to develop standard MEMS fabrication processes, to further upgrade the facility by purchasing some critical equipment, and to increase international activities for networking and collaboration of the Center. These will help (i) to complete the infrastructure for development of advanced industrial sensor systems and for easy collaboration with European research centers with the use of compatible equipments and standard fabrication procedures, (ii) to increase the involvement of the Center and Turkish industrial companies in FP7 projects, (iii) to extend the research subjects of the Center to new and exciting fields, (iv) to increase the interest of the industry and young scientists to MEMS, and (v) to create new job opportunities and better working conditions which can attract Turkish researchers abroad to Turkey, helping to reverse the brain-drain. In summary, this proposal will enable a high quality research center, which is already active in thematic priorities’ domain of the EC FP7 to become more integrated in the European Research Area.EU, Funded under FP7-REGPOT-2009-

Advanced MEMS For RF and Millimeter Wave Communications (AMICOM)

The approach of the information society has resulted in a tremendous increase in the volume of wireless communication often giving rise to bottle-necks in the communication systems. To alleviate this congestion there is pressure to widen the allocated frequency bands up to millimetre wavelengths and to have terminals that are able to support many standards. It is understood that conventional components and solutions have limitations that will make it difficult to fulfil these requirements. The last five years has seen the emergence of a technology, RF and microwave MicroElectroMechanical Systems (MEMS), that seeks to overcome these limitations. In this new technology mechanical and electrical functions are combined to improve the performance of existing devices, allow on-wafer device integration and the creation of completely new device systems called Advanced MEMSfor RF and Millimeterwave Communications "AMICOM".A consortium has been assembled that believes the merging MEMS technologies with 1Ctechnologies will lead to advanced microsystems that can operate over very broad-bandfrequency ranges. The microsystems will feature innovative functionalities, such as circuit redundancy, reconfigurability and power management. To realise this micro system concept, research and collaboration in many different fields is required including fabrication technology, materials, electromagnetics, mechanics, thermal and electrical modelling, characterisation, packaging and reliability. We believe that a Network of Excellence is the most appropriate vehicle with which to assemble and integrate the isolated competences that exist around Europe in this field. In this way a powerful research body will be created that can compete with the United States and Japan. The idea is to give to the industrial partners access to a large and transparent body of European competence to help them to enhance their competitiveness.NoE - Network of Excellenc

Prevention of sidewall redeposition of etched byproducts in the dry Au etch process

In this paper we present a new technique of etching thin Au film in a dual frequency inductively coupled plasma (ICP) system on Si substrate to prevent the redeposition of etched Au particles over the sidewall of the masking material known as veils. First, the effect of the lithography step was investigated. Then the effects of etch chemistry and the process parameters on the redeposition of etched Au particles on the sidewall of the masking material were investigated. The redeposition effect was examined by depositing a thin Ti film over the masking material acting as a hard mask. The results showed that depositing a thin Ti film over the masking material prevents the formation of veils after etching Au in plasma environments for submicron size structures. Based on the results of this study, we propose a new technique that completely eliminates formation of veils after etching Au in plasma environments for submicron size structures

A wireless implantable multichannel digital neural recording system for a micromachined sieve electrode

This paper reports the development of an implantable, fully integrated, multichannel peripheral neural recording system, which is powered and controlled using an RF telemetry link, The system allows recording of +/-500 mu V neural signals from axons regenerated through a micromachined silicon sieve electrode, These signals are amplified using on-chip 100 Hz to 3.1 kHz bandlimited amplifiers, multiplexed, and digitized with a low-power (<2 mW), moderate speed (8 mu s/b) current-mode 8-b analog-to-digital converter (ADC), The digitized signal is transmitted to the outside world using a passive RF telemetry link, The circuit is implemented using a bipolar CMOS process, The signal processing CMOS circuitry dissipates only 10 mW of power from a 5-V supply while operating at 2 MHz and consumes 4 x 4 mm(2) of area, The overall circuit including the RF interface circuitry contains over 5000 transistors, dissipates 90 mW of power, and consumes 4 x 6 mm(2) of area

A CMOS visible image sensor array using current mirroring integration readout circuitry

This paper reports the development of a CMOS visible sensor array using a high performance readout circuit called Current Mirroring Integration (CMI). The sensor element is a photodiode implemented using n-well and p+ -active layers available in any CMOS process. The current generated by optical excitation is mirrored and integrated in an off-pixel capacitor using the CMI readout circuit, which provides high injection efficiency, low input impedance, almost-zero and stable detector bias, and a high dynamic range. A 16x16 test array is fabricated using a 0.8µm CMOS process. Each detector pixel in the array occupies a 50µm x 50µm area with a fill factor of 60%. Operation of the fabricated test array is verified, and the output dynamic range is measured as 0.5V to 4.8

Determining the factors on moral standards in organizations by AHP Method

As each nation has its own morality rules and values based on the culture in macro level, each business company may have its own moral values and standards resulting from the corporate background and culture in micro level too. After all, there may be different parties playing role in setting those moral standards. This study aims to order the factors gathered by literature review those affect moral standards in business firms by Analytic Hierarchy Process (AHP). Results show that most important factor is social factors as mainly; social values, individual values and the demand and expectation of media in order at total. By these results it is aimed to reach a standard level and sustaining this level of one of the most important values in business life, work morality, with practices on results.Makro düzeyde her ulusun kültüründen kaynaklanan kendisine özgü ahlak kuralları olması gibi mikro düzeyde de her işletmenin kendi kurumsal geçmişi ve kültüründen kaynaklanan ahlaki değerleri ve standartları olabilmektedir. Bununla birlikte bu ahlaki standartların oluşmasında çeşitli taraflar rol alabilmektedir. Bu çalışma, örgütlerdeki ahlaki standartları etkileyen ve literatür taraması sonucunda elde edilmiş faktörlerin Analitik Hiyerarşi Prosesi (AHP) yöntemi ile önem sırasına göre hiyerarşik olarak sıralanması amacıyla yapılmıştır. Çalışma neticesinde göreli olarak önemli çıkan faktörler; ana kriter bazında toplumsal faktörler olurken; küresel ağırlıklara göre nihai sıralamada önemli olanlar sırasıyla toplumsal değerler; kişisel değerler medyanın talebi ve beklentileri olmuştur. Bulgular üzerinde yapılacak çalışmalarla, örgütlerdeki önemli değerlerin başında gelen iş ahlakında belirli bir standarda ulaşma ve bu standardı koruma amaçlanmaktadır

Atomic-layer-deposited zinc oxide as tunable uncooled infrared microbolometer material

ZnO is an attractive material for both electrical and optical applications due to its wide bandgap of 3.37eV and tunable electrical properties. Here, we investigate the application potential of atomic-layer-deposited ZnO in uncooled microbolometers. The temperature coefficient of resistance is observed to be as high as -10.4%K-1 near room temperature with the ZnO thin film grown at 120 degrees C. Spectral noise characteristics of thin films grown at various temperatures are also investigated and show that the 120 degrees C grown ZnO has a corner frequency of 2kHz. With its high TCR value and low electrical noise, atomic-layer-deposited (ALD) ZnO at 120 degrees C is shown to possess a great potential to be used as the active layer of uncooled microbolometers. The optical properties of the ALD-grown ZnO films in the infrared region are demonstrated to be tunable with growth temperature from near transparent to a strong absorber. We also show that ALD-grown ZnO can outperform commercially standard absorber materials and appears promising as a new structural material for microbolometer-based applications

A High Throughput Lab-On-A-Chip System for Label Free Quantification of Breast Cancer Cells under Continuous Flow

This paper presents an LOC system combining microfluidic DEP channel with a CMOS image sensor for label and lens free detection and real-time counting of MCF-7 cells under continuous flow. Trapped and then released MCF-7 cells are accurately detected and counted under flow with a CMOS image sensor integrated underneath the DEP channel, for the first time in the literature. CMOS image sensor can capture 391 frames per second (fps) that allows detection of the released cells flowing through the channel with a flow rate up to 130 mu l/min (0.468 m/s). Therefore, the proposed system is able to detect the cells under high flow where conventional techniques for cell quantification such as fluorescent tagging become unusable. Detected cells are automatically counted with a computer program and the counting accuracy of the whole system is 95%. (C) 2016 The Authors. Published by Elsevier Ltd

RF-MEMS teknolojisi ile faz dizili anten yapımı

TÜBİTAK EEEAG Proje30.06.201

Bilgi toplumu teknolojileri için anten sistemleri ve algılayıcılar

TÜBİTAK EEEAG01.10.2010Bu proje kapsamında, özellikle milimetre-dalga frekanslarında çalışan yeniden şekillendirilebilir anten, elektronik taramalı dizi anten ve yansıtıcı dizi anten tasarımı, üretimi ve ölçümleri yapılmıştır. Yeniden şekillendirilebilirlik özelliği için farklı teknolojiler kullanılmıştır. Huzmesi yönlendirilebilen sur biçimli mikroşerit yürüyen dalga anten dizisi X-bant uygulamalarında kullanılmak üzere tasarlamış, üretilmiş ve ölçülmüştür. Antenin ana huzmesinin istenilen yöne elektronik olarak döndürülebilmesini sağlayabilmek için mikroşerit hat üzerinde gerekli faz değişimini sağlayacak varaktör diyotlar kullanılmıştır. Yapılan EM benzetim ve ölçümler sonucu sur biçimli anten dizisinde, ana huzmenin diyot kontrolü ile tasarlandığı gibi 10 lik bir açı taraması yapabildiği gösterilmiştir. Bu kavram kanıtlaması şeklinde bir çalışmadır; huzmenin daha büyük açı aralığında tarama yapması için tasarımda yapılması gereken değişiklikler belirtilmiştir. MM-Dalga sabit genişlikli ve doğrusal sönümlenen yarık antenler tasarlanıp, üretilmiş ve antenin şeklinin, optik uyarımla bu iki yapı arasında değiştirilmesinin sağlanması durumunda ışıma örüntüsünün değiştirilebileceği gösterilmiştir. Proje kapsamında gerçekleştirilen bir diğer çalışmada da K ve Ka bantlarında bağımsız çalışabilen, RF MEMS anahtarlarla huzmesi elektronik olarak döndürülebilen dairesel polarizasyonlu yansıtıcı dizi anten tasarlanmış, üretilmiş ve ölçülmüştür. Çift frekanslı (24.4 GHz ve 35.5 GHz) dizi iç içe geçmiş farklı boyutlarda iki ayrık-halka dizisi şeklinde tasarlanmıştır. Huzme döndürme amacıyla her bir ayrık halkanın açısal konumunu RF MEMS anahtarlarla ayarlayarak, dairesel polarizasyonlu dalgaların fazları kontrol edilmektedir. Anten ODTÜ MEMS merkezinde geliştirilen yüzey mikro-işleme süreciyle üretilmiştir. Işıma örüntüleri ölçülmüş ve benzetim sonuçlarıyla karşılaştırılmıştır. Ölçümlerle, ana huzmenin, tasarlandığı gibi, Ka bandında 35°‟ye, K bandında 24°‟ye döndürülebildiği gösterilmiştir. Proje çalışmalarından sur biçimli mikroşerit anten dizisiyle ilgili hazırlanan makale Microwave and Optical Technology Letters adlı dergide yayınlanmak üzere kabul edilmiştir. Yansıtıcı dizi antenle ilgili makale de hazırlık sürecindedir. Saygın konferanslarda yedi bildiri sunulmuştur. Ayrıca, proje kapsamında üç yüksek lisans tez çalışması tamamlanmıştır.In this project, reconfigurable antenna, beam steering array and reflectarray have been designed, produced and measured, especially in mm-wave frequencies. To provide reconfigurability, different technologies have been considered. X-band electronically scanning meanderline microstrip traveling wave antenna array has been designed, produced and measured. To rotate the antenna beam to the desired direction, microstrip meander line has been loaded by varactor diodes that provide required phase shift values. EM simulations and rdiation pattern measurements of the meanderline antenna have demonstrated that the antenna has the capability to scan 10 with the control of varactors as designed. This is a proof-of-concept type study; alternative configurations to increase the scan range have also been discussed. MM-wave tapered slot antennas with a constant width and linear taper have been designed, produced and measured. It has been demonstrated that if the shape of the tapered slot antenna can be changed between constant width and linear taper structures by means of optical excitation, radiation pattern reconfigurability can be obtained. In another study accomplished in this project, electronically scanning circularly polarized reflectarray working independently in K and Ka bands has been designed, produced and measured. Dual band (24.4 GHz and 35.5 GHz) reflectarray has been designed as an interlaced array of split rings of two different sizes. In order to steer the beam, the phase of the incident circularly polarized wave is controlled by RF MEMS switches that modify the angular orientation of split-rings individually. The antenna has fabricated by using surface micromachining process developed in METU MEMS Center. Radiation patterns of the antenna are measured and compared with the simulations. It has been shown that the reflectarray is capable of beam switching to 35° in Ka band, 24° in K band as required. One journal paper on meanderline antenna has been accepted to be published in Microwave and Optical Technology Letters. Preparation of manuscript on reflectarray is under progress. Seven conference papers have been presented in well known Conferences. Furthermore, three Master Thesis studies have been accomplished during the project