resulting in relatively low data throughput. On the other hand, another type of the new memories based on a solid state We report a novel nonvolatile dual-layered electrolytic electrolyte [5], in which ions such as Ag+ or Cu+ move along resistance memory composed of a conductive Cu ion the applied field and form the conductive bridge in the activated layer and a thin insulator for the first time. An electrolyte, is a promising candidate from the viewpoints of ON/OFF mechanism of this new type memory is postulated high speed switching and low set/reset current. Previous as follows: Cu ions pierce through the insulator layer by studies on the memories, however, seem to show their applied electric field, the ions form a Cu conductive bridge in insufficient retention. the insulator layer, and this bridge dissolves back to the ion To realize both high speed switching and sufficient activated layer when the field is reversed. The 4 kbit memory retention, we have newly developed a dual-layered array with IT-IR cell structure was fabricated based on 180 electrolytic resistance memory utilizing Cu conductive bridge nm CMOS process. Set/reset pulses were 5 ns, 110 gtA and 1 combined with a thin insulator. ns, 125 gA, respectively. Those conditions provide large set/reset resistance ratio of over 2 orders of magnitude and Memory Design satisfactory retention. Essential characteristics for high capacity memories including superb scalability down to 20In a solid state electrolytic memory, metallic ions such as nmo, sufficient endurance up to 107 cycles and preliminary Ag+ or Cu+ play an essential role in fast forming a conductive data for 4-level memory are also presented. These bridge when the electric field is applied. But without the field, characteristics promise the memory being the next generation the bridge should steadfastly keep the shape for the data high capacity nonvolatile memory even before the scaling retention. It seems hard to solve these incompatible limitation of flash memories is encountered. characteristics within a single layer. Therefore we divided the role into respective two layers: the conductive ion activated Introduction layer and the resistance change layer of the insulator as shown in Fig. 1. The resistance change layer is thin enough An imminent scaling limit of flash memories accelerates for the activated ions to pierce through the layer rapidly in the search for the new memories and so far several types of the electric field. The conductive bridge is stable in the layer resistive memories are proposed, such as phase change when no electric field is applied. When the reverse field is memory [1, 2], oxide base resistance change memory [3, 4] applied, the bridge is dissolved back to the ion layer, where and so on. However, each memory seems to have inherent both the electric field and joule heat are thought to be main drawbacks such as large reset current and/or slow set speed, driving forces. Because the insulator layer is thin enough, o o a %^o Cu od 1 l z | CT e | og g uC Gd Cu-Te base conz u...

An inexpensive and practical mastering technology was developed using a blue-laser optical system with a wavelength of 405 nm and numerical aperture (NA) of 0.95 comprising an inorganic photoresist. The resist system showed a higher resolution for a successful 130 nm pit patterning than that obtained by an ordinary organic photoresist system. Based on this technology, a read only memory (ROM) disc with a recording capacity of 25.2 GB on a 120-mm-diameter surface was mastered at a high recording speed of 4.92 m/s. The disc showed a reasonable jitter value of 8.0% using a conventional equalizer, 4.6% using a limit equalizer and a push-pull signal using a conventional readout optical system of ¼ 405 nm and NA ¼ 0:85.

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We propose the use of a high numerical-aperture (NA) microlens formed by plasma etching for an optical recording application. It was found through optical recording experiments that a microlens formed by plasma etching is applicable to a tiny objective lens.