@phdthesis{Kaletta2014, author = {Kaletta, Udo Christian}, title = {Entwicklung CMOS kompatibler Oberfl{\"a}chenwellenfilter (SAW) basierend auf Aluminiumnitrid f{\"u}r die Biosensorik und drahtlose Datenkommunikation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-31993}, school = {BTU Cottbus - Senftenberg}, year = {2014}, abstract = {Einleitung: Akustische Oberfl{\"a}chenwellenfilter (SAW Filter) finden in zahlreichen drahtlosen und drahtgebundenen Kommunikationstechnologien sowie in der Sensorik ihren Einsatz. Dabei f{\"u}hrt der Trend hin zu immer preiswerteren und kompakteren L{\"o}sungen mit noch mehr Funktionalit{\"a}t und noch geringeren Stromverbr{\"a}uchen. Die Anwendungen erstrecken sich dabei von ultraenergiesparenden Kommunikationssystemen (z. B. f{\"u}r Sensorknoten) bis hin zu preiswerteren Multisensorarrays in der Sensorik (z. B. Biosensoren) sowie auf einem Chip integrierten Mikrofluidik Systemen (z. B. Mikroliterpumpen). Eine L{\"o}sung stellt die Integration der SAW Filter auf einem Chip zusammen mit integrierten Schaltkreisen (IC) in der sogenannten komplement{\"a}ren-Metall-Oxid-Halbleiter (CMOS) Technologie dar. Da es sich hierbei um ein neues Forschungsgebiet handelt und nur wenige Forschergruppen auf diesem Gebiet arbeiten sind umfangreiche wissenschaftliche Untersuchungen notwendig, um eine vollst{\"a}ndige Integration der SAW Filter zu erm{\"o}glichen. Das einzige reinraumkompatible piezoelektrische Material mit einem ausreichend hohen elektromechanischen Kopplungsfaktor (K2) sowie einer hohen akustischen Ausbreitungsgeschwindigkeit (vAlN = 5760 m/s [Bu 2006]) f{\"u}r hohe Arbeitsfrequenzen (bis ~6 GHz) ist dabei Aluminiumnitrid (AlN). Daf{\"u}r muss es hoch c-achsenorientiert (<2°) aufgewachsen werden. Ein großes Problem bei der Integration ist das elektromagnetische {\"U}bersprechen (Crosstalk), welches besonders auf den f{\"u}r die CMOS Technologie notwendigen niederohmigen Siliziumsubstraten auftritt. Ziel: Diese Doktorarbeit untersucht die M{\"o}glichkeit der Integration von AlN basierten SAW Filtern mit Hilfe von diskreten Bauelementen, aufgebaut mit CMOS kompatiblen Schichtsystemen, in Hinblick auf eine sp{\"a}tere CMOS kompatible Vollintegration. Ergebnisse: Es konnte gezeigt werden, dass AlN basierte Filter mit Hilfe von CMOS kompatiblen Materialien und Prozessschritten hergestellt werden k{\"o}nnen. Außerdem konnte gezeigt werde, dass AlN sehr gut (full width at half maximum, FWHM: 1,27° - 1,9°) c-achsenorientiert aufgewachsen werden kann. Umfangreiche Simulationen, die mit Hilfe der finiten Element Methode (FEM) durchgef{\"u}hrt wurden, zeigten akustische Wellen (Rayleighwelle R0 und an der Oberfl{\"a}che gef{\"u}hrte Volumenwelle R1) mit Geschwindigkeiten von circa 4200 m/s (R0) bzw. 5200 m/s (R1) im technisch relevanten Frequenzbereich (~2,4GHz). Es wurde festgestellt, dass die akustische Reflektivit{\"a}t von Wolfram basierten Fingerelektroden circa ein bis zwei Gr{\"o}ßenordnungen h{\"o}her liegt als bei Aluminium basierten Elektroden. Hergestellte SAW Filter zeigten maximale Resonanzfrequenzen von 3,3 GHz bei einer Wellenl{\"a}nge von 1,68 µm, diese k{\"o}nnen noch auf bis zu 6,6 GHz bei einer minimalen Wellenl{\"a}nge von 0,8 µm gesteigert werden. In dieser Arbeit konnte erstmals ein elektromagnetisches {\"U}bersprechen (Crosstalk) von unter -65 dB auf standardm{\"a}ßig niederohmigen Siliziumsubstraten gezeigt werden. Erste optimierte SAW Filteranwendungen zeigten typische Frequenzantworten mit guter Performance.}, subject = {Surface acoustic wave; Crosstalk; Oberfl{\"a}chenwellenfilter; Aluminiumnitrid; SAW Filter; CMOS; Oberfl{\"a}chenwellenfilter}, language = {de} } @phdthesis{KalishettyhalliMahadevaiah2023, author = {Kalishettyhalli Mahadevaiah, Mamathamba}, title = {Process development and electrical characterization of CMOS-integrated memristive devices for emerging non-volatile memory applications}, doi = {10.26127/BTUOpen-6557}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-65571}, school = {BTU Cottbus - Senftenberg}, year = {2023}, abstract = {Energy efficiency is vital for future low-power electronic applications. This ultra-low power consumption requirement enables the research beyond the conventional charge-based memories. Further, reliability, high scalability, fast switching, CMOS compatibility, high endurance, etc., are some of the characteristics envisaged by the new generation of emerging non-volatile memories (NVMs). A memristor or OxRAM is one among the many emerging NVMs, which can exhibit the aforementioned characteristics, and it has the potential to replace the power-hungry conventional NVMs. The memristive devices have the advantage of monolithic integration with the CMOS logic, which enables the widening of their application areas. Despite their various advantages, the reliability, forming voltages, and variability of the devices pose a hurdle to their wide commercial usage. Hence, it is crucial to identify these factors and mitigate them. This thesis addresses these issues through fabrication process improvements, electrical characterization techniques, and device-engineering methods. The improvements in the fabrication processes reduced the pristine state currents of the memristive devices. It impacted the reliability and resistive switching performance of the memristive devices directly. To further improve the performance, the memristive devices are integrated into the 130 nm BiCMOS baseline technology of IHP. Additionally, dedicated test structures are developed to monitor and control the fabrication process steps through in-line electrical characterization. Further, the forming current and voltage values, along with their dispersions in the 4 kbit memristive arrays, were reduced by utilizing the electrical characterization techniques. Accordingly, the forming operations were performed at high operating temperatures using incremental step pulse and verify algorithm (ISPVA). In contrast to the well-known method of increasing the current compliance (1R) or the gate voltage of the transistor (1T-1R) to increase the conduction filament size, a thin layer of Al2O3 is added. This device engineering technique reduced the variability in both LRS and HRS currents of the memristive devices. Additionally, the conduction filament properties in both states are modeled by using the quantum point contact (QPC) model. Finally, harnessing the intrinsic variability of the memristive devices for neuromorphic computing applications is demonstrated. The reliability of the devices is assessed through endurance and retention characteristics.}, subject = {Memristive devices; RRAM; ISPVA; Forming; Variability; Formierspannung; Variabilit{\"a}t; Dispersion; Leitungsdraht; Neuromorphe Anwendungen; CMOS; Nichtfl{\"u}chtiger Speicher; Memristor; Modellierung; Dispersion}, language = {en} } @phdthesis{MatbaechiEttehad2021, author = {Matbaechi Ettehad, Honeyeh}, title = {Dielectrophoretic manipulation of yeast cells using CMOS integrated microfluidic}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-55315}, school = {BTU Cottbus - Senftenberg}, year = {2021}, abstract = {The rapid detection of infectious diseases is still an unsolved problem since their identification must be carried out either by cultivation or DNA analysis in a laboratory. The development of point-of-care (PoC) is a current development trend that requires further technological impulses to produce reliable and cost-effective systems. By miniaturizing and integrating microfluidic and electronic components, the advantages of electronic methods can be transferred to the field of PoC testing. The combination of complementary metal-oxide-semiconductor (CMOS) technology with microfluidic platforms allowed the development of fully functional sample-to-result LoC setups, which served the portability of the device even out of the laboratory or hospitals. CMOS-based LoC device can control and manage the data from sensors, microfluidics, and actuators. Dielectrophoresis (DEP) is a non-destructive and non-invasive method promising to be used in PoC medical applications. Utilizing MEMS technology and fabrication of microelectrodes allow DEP to be applied in biomedical applications such as cell manipulation and separation with high speed, sensitivity and without any labeling. Cell detection and separation occupy an important place in diagnostics of viral and infectious diseases such as Influenza and COVID-19. Therefore, rapid, sensitive, and automated LoC devices are needed to detect such diseases. Starting from this point of view, manipulating the cells as a way to detect them using DEP was decided as the main objective of the thesis. This work aimed at developing a miniaturized CMOS integrated silicon microfluidic device, in line with a standard CMOS procedure, for characterization and manipulation of live and dead yeast cells using the DEP technique. Understanding the relationship between the microelectrode's geometry and the magnitude of DEP force, the microfluidic devices can be designed to produce the most effective DEP implication on biological samples. In this work, interdigitated electrode arrays (IDEs) were used to manipulate the cells. This microelectrode was primarily used to detect microorganisms in a solution, based on the measurement of the variation of the dielectric constant by the concentration of the microorganisms. Therefore, finite element simulations were performed to optimize this microelectrode and adapt it to our application. Thus, the IDEs were optimized as a function of finger width and spacing between adjacent fingers. One of the most serious matters related to DEP-based microfluidic devices is that the DEP spectra of the targeted cell should precisely be known. Therefore, the DEP spectrum analysis of various cell suspensions with different medium conductivities was studied comprehensively by finite element simulation and experimentally. This study presented an optimized trapping platform for both detection and separation applications in terms of electrode dimension and electrical parameters.}, subject = {Dielectrophoresis (DEP); Yeast cell; Cell manipulation; Interdigitated electrodes (IDEs); CMOS-integrated microfluidic Lab-on-a-chip; Dielektrophorese (DEP); Hefezelle; Zellmanipulation; Interdigitalelektroden (IDEs); CMOS-integriertes mikrofluidisches Lab-on-a-chip; CMOS; Lab on a Chip; Dielektrophorese; Saccharomyces cerevisiae; Mikrofluidik; Biomedizinische Technik}, language = {en} }