映像情報メディア学会誌 Vol. 73, No. 4, pp. 633 ～ 639（2019） 633 （32） 1. Introduction For over one decade, the search for a two-terminal non-volatile low energy switch has preoccupied many research centers and industry worldwide 1) . Well over 4, 000 research papers as summarized in 1) attest to the fact that such a device is a central issue of the age of AI. In their many varieties, Resistive Random Access Memory (ReRAM or RRAM) cells seem able to provide multi-level fast switches. However, such devices which are usually based on ionic motion and filaments (due to various breakdown mechanisms) and organic materials, are highly stochastic. Recently, this lack of determinism has been exploited by time-dependent programming in Stochastic Computing. Other schemes such as Cross Point memory cells (usually based on Chalcogenides), and arrays of synapses based on related cross-point technologies (e.g., IBM's True North "Brain Chips" 2) ), fail as high-speed and low energy cells because the synapses requires a thermally-activated phase transition. Metal-insulator phase transitions (MITs) exist in a variety of materials. However, many materials may show MITs at a narrow temperature window or depend on charge traps and other defects. A time-independent, non-stochastic, multi-level, low energy, non-volatile artificial synapse has evaded researchers until now. This paper introduces the elementary device physics of a CeRAM cell and the multi-level programmable synaptic weight (resistance) in Section 2. Results from tested devices are shown in Section 3. Conclusions presented in Section 4 show further reasons for the promising characteristics of this device. 2. CeRAM Device Physics In this section, a summarized version of the device physics of a CeRAM cell is described. The key technological breakthrough that makes the CeRAM device to behave as described below is reported elsewhere 3) . From the point of view of circuit operation, a CeRAM cell is a resistive switch - for a memory storage application. Fig. 1 shows resistance levels. However, the underlying physics involves a novel mechanism which leads to an MIT and its reverse, IMT (Insulator-to-Metal Transition). For reasons that will be made clear below, the materials that are useful for CeRAM are p-typed semi- insulating Transition Metal Oxides (TMOs), Perovskites and Chalcogenides with transition metals. Such Carlos A. Paz de Araújo † 4 章 工学と経営学の融合によるイノベーションマネージメント事例 4-2 A New Synapse For Non-Von Neumann Architectures Based On Switching A Correlated-Electron Random Access Memory (CeRAM) Cell 特集　アントレプレナー・エンジニアリング研究委員会設立 20 周年記念 †University of Colorado, USA/Symetrix Corporation, USA Fig.1 An experimental plot of Resistance versus Applied Voltage for a two-states CeRAM. R for 10×10 μ㎡ V 1/2 ［V］ 1/2 0 0.5 1 1.5 6.E＋03 5.E＋03 4.E＋03 3.E＋03 2.E＋03 R［Ω］ 1.E＋03 0.E＋00 －1.E＋03 Appendix A R OFF R ON Keywords: Non-volatile memories, new materials, neuromorphic computing, device physics