To Investigate the Data Retention and Endurance for the Optimized Gadolinium (Gd) Nanocrystal Flash Memory

• Main Authors: Yu Kai Chen, 陳育楷
• Other Authors: C. S. Lai
• Format: Others
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/85754766683502368230

碩士 === 長庚大學 === 電子工程學研究所 === 96 === Recently, floating gate memory devices widely be used in non-volatile data storage application. However, there are some major issues including devices scaling limitation, higher operation voltage and poor data retention time needed to overcome for conventional floating gate memory which employed poly-silicon as the charge storage layer. In order to solve these above issues, the nanocrystal memory devices which with discrete charge storage nodes have been proposed to be a possible candidate for the replacement of floating gate memory. In this thesis, we propose a Gadolinium (Gd) nanocrystal memory structure for nonvolatile flash memory application and also find the optimized post deposition annealing (PDA) temperature. The Gd nanocrystal memory with optimum PDA treatment exhibits high Gd-NC density (6.1×1011/cm2) and large memory window (>3V). The speed of program can be at 1ms and erase at 1s. Besides, data retention time for various (PDA) temperature treatment, blocking oxide layer and charge storage layer has been investigated. It can be discriminated the direct tunneling through the tunneling oxide or blocking. Concluding the measurement results, the memory with thicker charge storage layer shows smaller charge loss rate than other ones at 85℃ and the constant electric field. It also shows the same phenomenon of the memory with thicker blocking. Finally, the Gd nanocrystal memory with optimum condition as well as exhibits superior data endurance characteristics.