Haris Pozidis

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To my beautiful wife for her love and encouragement To my brother for his continuous support To my parents, my first teachers ii ACKNOWLEDGMENTS I would like to express my sincere gratitude and thanks to my advisor Dr. Chika Nwankpa, for his continuous guidance, support and friendship. Since the beginning of my graduate career at Drexel, and up to the very(More)
Multiple-Level Cell (MLC) storage provides increased capacity and hence reduced cost-per-bit in memory technologies, thereby rendering such technologies suitable for big data applications. In Phase-Change Memory (PCM), however, MLC storage is seriously hampered by the phenomenon of resistance drift. We present a readout circuit for PCM specifically designed(More)
In the probe-based storage concept being pursued by IBM, a MEMS based micro-scanner is used to position the storage medium relative to the read/write probes. To achieve repeatable positioning over a large storage area, it is necessary to have medium-derived position information. Dedicated servo-fields are typically employed to obtain medium-derived position(More)
Topographic engraving of structures in polymer surfaces attracts widespread interest for application in imprint lithography and data storage. We study the nonlinear interaction of nanoindents written in close proximity, 20-100 nm, to one another in a highly cross-linked polystyrene matrix. The indents are created thermomechanically by applying heat and(More)
A non-resistance readout scheme for high density multi-level PCRAM is described. Non-resistance read metric with drift resilient nature is enhanced to be suitable for high density memory array with large parasitic time constant. 1G PCM cells in 25nm technology are structured in the form of a single bank of a 16G cell chip with the hierarchical bit-line(More)
Position sensing with resolution down to the scale of a single atom is of key importance in nanoscale science and engineering. However, only optical-sensing methods are currently capable of non-contact sensing at such resolution over a high bandwidth. Here, we report a new non-contact, non-optical position-sensing concept based on detecting changes in a(More)
We present an improved conductive-mode atomic force microscopy (C-AFM) method by modulating the applied loading force on the tip. Unreliable electrical contact and tip wear are the primary challenges for electrical characterization at the nanometer scale. The experiments show that force modulation reduces tip wear by a factor of three and enhances(More)
In this work we propose an accelerated stochastic learning system for very large-scale applications. Acceleration is achieved by mapping the training algorithm onto massively parallel processors: we demonstrate a parallel, asynchronous GPU implementation of the widely used stochastic coordinate descent/ascent algorithm that can provide up to 35×(More)
Scanning probe microscopy employing conductive probes is a powerful tool for the investigation and modification of electrical properties at the nanoscale. Application areas include semiconductor metrology, probe-based data storage and materials research. Conductive probes can also be used to emulate nanoscale electrical contacts. However, unreliable(More)
There is a significant need for nanoscale electrical characterization of materials. However, unreliable tip apexes have severely hampered the usage of scanning probe techniques for nanoscale electrical characterization. Encapsulated conductive probes with conductive cores comprising of Platinum Silicide and an insulating encapsulation are powerful tools for(More)