Recent Advances on Neuromorphic Systems Using Phase-Change Materials

Abstract

Realization of brain-like computer has always been human’s ultimate dream. Today, the possibility of having this dream come true has been significantly boosted due to the advent of several emerging non-volatile memory devices. Within these innovative technologies, phase-change memory device has been commonly regarded as the most promising candidate to imitate the biological brain, owing to its excellent scalability, fast switching speed, and low energy consumption. In this context, a detailed review concerning the physical principles of the neuromorphic circuit using phase-change materials as well as a comprehensive introduction of the currently available phase-change neuromorphic prototypes becomes imperative for scientists to continuously progress the technology of artificial neural networks. In this paper, we first present the biological mechanism of human brain, followed by a brief discussion about physical properties of phase-change materials that recently receive a widespread application on non-volatile memory field. We then survey recent research on different types of neuromorphic circuits using phase-change materials in terms of their respective geometrical architecture and physical schemes to reproduce the biological events of human brain, in particular for spike-time-dependent plasticity. The relevant virtues and limitations of these devices are also evaluated. Finally, the future prospect of the neuromorphic circuit based on phase-change technologies is envisioned.

A Review of Germanium-Antimony-Telluride Phase Change Materials for Non-Volatile Memories and Optical Modulators

“…As shown in Figure 13, each memory cell comprises a PCRAM device using a conventional mushroom-type device and a selection transistor. The cell can be accessed by a bit line connected to the gate of the transistor and a word line connected to the top electrode of PCM element [70,71]. Metal-oxide-semiconductor field-effect transistors (MOSFETs) and bipolar transistors (BJTs) are the transistors that have been used in the industry for decades for selector devices.…”

Flexible Neuromorphic Electronics for Computing, Soft Robotics, and Neuroprosthetics

“…Artificial synapses have been developed based on various structures, materials, and mechanisms to mimic the structure and synaptic plasticity of biological synapses. Conventional memory mechanisms (e.g., conductive filament, [54,75,[77][78][79][80][81][82][83][84][85][86] Schottky junction, [87][88][89] charge trapping, [82,[90][91][92][93][94][95] phase change, [75,[96][97][98] ferroelectricity, [99][100][101][102][103][104][105][106][107] ion migration [4,51,74,108] ) have been extended to the implementation of synaptic properties. Artificial synapses, i.e., transistors that exploit electrochemical reactions have also been developed.…”

Neuromorphic Computing with Memristor Crossbar

“…All the two‐terminal solid‐state memristors can be considered synaptic devices regardless of the device materials, physical mechanisms, and switching phenomena . From the structural perspective, a memristor is a two‐terminal nanoscale device similar to the biological synapse.…”