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Phase change memory (PCM), which exploits the phase change behavior of chalcogenide materials, affords tremendous advantages over conventional solid-state memory due to its nonvolatility, high speed, and scalability. However, high power consumption of PCM poses a critical challenge and has been the most significant obstacle to its widespread(More)
Although synaptic behaviours of memristors have been widely demonstrated, implementation of an even simple artificial neural network is still a great challenge. In this work, we demonstrate the associative memory on the basis of a memristive Hopfield network. Different patterns can be stored into the memristive Hopfield network by tuning the resistance of(More)
We have investigated electrical properties of a chalcogenide-based device with naturally oxidized Al electrodes. Intermediate-resistance (IR) states exhibited by current–voltage (I–V) characteristics, dynamic resistance change as a function of pulse height and decay behavior from a low-resistance state of such a device make multi-state storage feasible.(More)
Lateral single-channel (SC) and multi-channel (MC) phase-change memory (PCM) cell structures are numerically analyzed for multi-state storage based on their temperature distributions and their programming characteristics. As studied by finite element modeling (FEM), shorter pulses lead to more gradual transition from the set to the reset state of these(More)
We studied the possibility of achieving very fine-pitch dot arrays with a pitch of 20 nm × 20 nm using 30 keV electron beam (EB) drawing on negative calixarene resist. In order to form such patterns, we studied the dependence on resist thickness of the dot size and the packing. We propose EB drawing on an extremely thin film for very highly packed dot-array(More)
Inclination atomic force microscope (AFM) imaging has been studied on the possibility to observe a pattern sidewall in contact mode or digital probing (step-in) mode for a line edge roughness (LER) or line width roughness (LWR). Analysis of the AFM tip bending and slipping indicates that it is serious problem to measure and control very fine patterns within(More)
A huge internal stress is usually induced by a volume change in chalcogenide as the storage media in phase-change memory (PCM) devices and deteriorates their performance. In this work, doping N into GeTe with a fast operation speed (ns order) is investigated with the aim of reducing the volume change upon crystallization. The volume change upon(More)
We have studied a possibility to read small pits in electron beam (EB) resist layer using a near-field optical probe for ultrahigh density optical storage. For the reading, we used small near-field optical probe in prototype atomic force cantilevered SNOM, which has an ability to obtain both atomic force microscope (AFM) and scanning near-field microscope(More)
We have studied graphoepitaxy to make nanodots or nanolines ordered along electron beam (EB)-drawn resist guide using block copolymers (BCPs) of polystyrene-polydimethylsiloxane (PS-PDMS). We found out that the number n of ordered molecular dot arrays in the line gap increases stepwise with the gap between guide lines. The n self-assembled dot arrays were(More)
By introducing electrical connections into the chamber of a scanning electron microscope (SEM) via its holder assembly, it has become feasible to in situ observe and electrically characterize electronic devices. The in situ SEM was applied to investigate electric-pulse-induced behavior of Ge(2)Sb(2)Te(5) in a lateral phase-change memory cell. Randomly(More)