A novel scalable and stackable nonvolatile memory technology suitable for building fast and dense memory devices is discussed. The memory cell is built by layering a storage element and a selector. The storage element is a Phase Change Memory (PCM) cell [1] and the selector is an Ovonic Threshold Switch (OTS) [2]. The vertically integrated memory cell of one PCM and one OTS (PCMS) is embedded in a true cross point array. Arrays are stacked on top of CMOS circuits for decoding, sensing and logic functions. A RESET speed of 9 nsec and endurance of 10 6 cycles are achieved.One volt of dynamic range delineating SET vs. RESET is also demonstrated.

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A novel construction of optically controlled microwave filter is proposed and studied. Inter-coupled split-ring resonators (SRR) were directly implemented on a microstrip transmission line to build a bandpass filter with a very large fractional bandwidth. Highly photosensitive cadmium sulfide (CdS) thin film was utilized to provide the capability of switching to the structure. A low sheet resistance of 300 ohms per square was achieved for CdS thin film under illuminated condition. When the photosensitive CdS thin film is deposited on the microstrip line, the filtering phenomenon induced by the inter-coupled SRR can be controlled optically. It has been demonstrated in both simulation and experimental measurement that the transmission coefficient is switched from 19 dB to 1.5 dB at 5 GHz while the passband region is centered at 14 GHz. Simulation results indicate that the insertion loss can be improved when the SRR cell number or the ring spacing is decreased.Index Terms-Bandpass filter, cadmium sulfide, microstrip, split-ring resonator.

A novel construction of microwave switchable lowpass filter based on electromagnetic bandgap (EBG) and cadmium sulfide (CdS) thin film is proposed. Linearly tapered slot‐array EBG structure is well known for its exceptional stopband ability and compact physical size. When the illumination‐sensitive CdS thin film is deposited on the perforations of the EBG structure, the stopband phenomenon induced by tapered slot‐array can be controlled by optical means. Innovative “conductive islands” were introduced to reside in the center of each perforation in order to enhance the optical switching. It has been demonstrated in both simulation and experimental measurement that the transmission coefficient is switched from 31.3 to 5.6 dB at 13 GHz when the gap width between the conductive island and the perforation is 30 μm. As the gap width decreases, the insertion loss can be reduced. Simulation result indicates that the insertion loss can be improved to around 1 dB at 13 GHz when the gap width is decreased to 5 μm. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2238–2242, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22665