Shih-g Chen

Developments in nanocrystal memory

Flash nonvolatile memory has been widely applied in portable electronic products. However, traditional flash memory is expected to reach physical limits as its dimensions are scaled down; the charges stored in the floating gate can leak out more easily through a thin tunneling oxide, causing a serious reliability issue. In order to solve this problem, discrete nanocrystal memory has been proposed and is considered to be a promising candidate for the next generation of nonvolatile memories due to its high operation speed, good scalability, and superior reliability. This paper reviews the current status of research in nanocrystal memory and focuses on its materials, fabrication, structures, and treatment methods to provide an in-depth perspective of state-of-the-art nanocrystal memory.

Influence of Nanocrystals on Resistive Switching Characteristic in Binary Metal Oxides Memory Devices

The resistive random access memory has attracted much attention for nonvolatile memory application in recent years. However, there is an issue about variations of switching parameters such as set voltage and conductivity of resistance state in resistive switching memory. The variations may cause not only switching error but also reading error during operation. We investigated the switching performance of binary metal oxide as a resistive switching layer embedded with and without metal nanocrystals. Compared with the conventional memory structure, the memory embedded with metal nanocrystals shows better stability, preferable uniformity for the next generation nonvolatile memory application.

Improvement of resistance switching characteristics in a thin FeOx transition layer of TiN/SiO2/FeOx/FePt structure by rapid annealing

In this paper, the influence of a 600 °C rapid thermal annealing for 60 s on the improvements of resistance switching behaviors in a TiN/SiO2/FeOx/FePt structure is reported. It is found that besides the distinct reduction in memory switching parameters in forming voltage, set/reset voltages, and their dispersions, the resistance ratio of high-resistance state to low-resistance state is also enlarged after annealing. The effects of annealing on improving the resistance switching properties are discussed by x-ray diffraction and x-ray photon-emission spectra depth profile results. Additionally, good retention characteristics are exhibited in the annealed TiN/SiO2/FeOx/FePt resistance switching memory.

Investigation for coexistence of dual resistive switching characteristics in DyMn2O5 memory devices

Dual bipolar resistive switching characteristics were observed in the Pt/DyMn2O5/TiN memory devices. The typical switching effect could be attributed to the formation and rupture of the conducting filament in DyMn2O5 films. The parasitic switching behavior can be observed in the specific operation condition. Dual bipolar resistance switching behaviors of filament-type and interface-type can coexist in the devices by appropriate voltage operation. The operating current can be significantly decreased (100 times) by parasitic switching operation for portable electronic product application. In addition, the relationship between filament-type and interface-type switching behaviors were studied in this paper.

Effect of Top Electrode Material on Resistive Switching Characteristics in MnO

a. Department of Electronics Engineering & Institute of Electronics, National Chiao Tung University, Hsin-Chu 300, Taiwan, R.O.C. b. Department of Physics and Institute of Electro-Optical Engineering, & Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan, R.O.C. c. Green Energy & Environment Research Labs. , Industrial Technology Research Institute, Hsinchu 310, Taiwan, R.O.C. d. Department of Electrical Engineering & Institute of Electronic Engineering, National Tsing Hua University, Taiwan