Thermal analysis for observing conductive filaments in amorphous InGaZnO thin film resistive switching memory

Abstract

Local heat produced by an electrical path inside the memory was detected and imaged by the method “Thermal Analysis.” It turned out that the visualized heat spots were conductive filaments (CFs) formed between interlayers of Pt/amorphous InGaZnO (a-IGZO). By using the thermal analysis, the location of CFs and their surface temperature was detected. This method indicated that there was a lot of emitted heat when the memory cell was switched off. It is thought to be accumulated heat causing disruption of the CFs. With great range of measurement, it was found that some memory cells drive with a single CF and others drive with multiple CFs. For the formation of CFs, it is assumed that there are CFs formation sites such as oxygen-related defects, roughness of the layer of a-IGZO, and so on. This method “Thermal analysis” can contribute to detection of the CF's location, the number of CFs, and thermal activity inside the memory devices.

Interfacial Chemistry-Induced Modulation of Schottky Barrier Heights: In Situ Measurements of the Pt–Amorphous Indium Gallium Zinc Oxide Interface Using X-ray Photoelectron Spectroscopy

“…There is increasing interest in using transparent amorphous oxide semiconductors (TAOS) for ubiquitous electronic devices due to their excellent electronic performance and their potential for novel transparent electronics. The most promising TAOS material to date is amorphous-indium gallium zinc oxide (a-IGZO), which is currently used as an active material for thin-film transistors (TFTs) in active matrix displays. , Other applications for a-IGZO include photodetectors, Schottky − and pn diodes, metal–semiconductor field-effect transistors, , Schottky-barrier TFTs, strain gauges, chemical and biological sensors, resistive random access memory (RRAM), , and memristors . A benefit of a-IGZO is that there is a fairly high degree of flexibility on the range of In/Ga/Zn ratios used for the active semiconductor in a TFT or as a switching layer in RRAM .…”

Effect of Oxygen-deficiencies on Resistance Switching in Amorphous YFe0.5Cr0.5O3−d films

“…As shown in the Figure S2 of Supporting Information, the resistance in LRS is independent of the area of electrode, and the resistance in HRS shows a linear dependence on the area of electrode. These results further suggested the filamentary switching mechanism works well in the a-YFCO films 36 37 . In fact, the oxygen-deficiency is responsible for the creation of a CF network across the device.…”

“…However, each step must be carefully controlled to avoid any heating or chemical damaging/etching effect on the amorphous film to prevent crystallization during the entire fabrication process of the devices because the amorphous films was prepared at low temperature. Therefore, the amorphous film that can be prepared at high temperature should beneficial to the fabrication of the RS devices and thus its’ applications 35 36 37 38 . YFe 0.5 Cr 0.5 O 3 (YFCO) is a perovskite oxide with an orthorhombic structure 39 .…”

One Transistor–Two Memristor Based on Amorphous Indium–Gallium–Zinc-Oxide for Neuromorphic Synaptic Devices

“…The resistance switching phenomena of memristors have been observed in various oxide-based materials, such as HfO x , − TiO x , − AlO x , , TaO x , , and ZnO. , Among them, amorphous indium–gallium–zinc oxide (IGZO) films have recently been found to show resistance switching behaviors. − Furthermore, IGZO is one of the most mature channel materials for thin-film transistors (TFTs) owing to its high carrier mobility, high transparency, flexibility, wide range of process temperatures, and high-yield process. − As IGZO can be used to make both transistors and memristor devices, neuromorphic systems can be manufactured without the complicated process needed to integrate neuron circuits and synaptic devices.…”