Novel Ion Bombardment and Plasma Passivation Techniques for Nonvolatile Memory Applications

• Main Authors: Sheng-hsien Liu, 劉聖賢
• Other Authors: Wen-luh Yang
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/8wc696

博士 === 逢甲大學 === 電機與通訊工程博士學位學程 === 102 === As the charge-trapping flash (CTF) memory is scaled down to 1x-nm generation, the lack of storage charges can cause serious reliability problems in high-package density condition, such as data retention, endurance, disturbance, etc. This means the problem of insufficient storage charges limits the possibility of device size scaling-down. To smoothly promote the CTF memory from 2x- to 1x-nm generations, this study has devoted to the development of novel “ion bombardment (IB)” and “NH3 plasma treatment (PT)” modules. We used the IB and NH3 PT techniques to fabricate high-performance charge storage layers, which cover high-efficiency and excellent-reliability characteristics, for solving the challenges from next-generation CTF memory. For high-k dielectric storage layer, we used the IB process to increase the number of trap sites in storage layer and change the trapping centroid location. Meanwhile, we adopted the NH3 PT to improve the IB-induced reliability degradation. It is notable that the NH3 PT is sensitive to shallow trap site and insensitive to deep trap sites. Results reveal that the operation efficiency and reliability properties can be simultaneously improved using the optimal combination of IB and NH3 PT techniques. For double-layer (DL) metal nanocrystal (NC) storage layer, the IB technique is a novel manufacturing technology. Using IB technique, an ultra-thin high-quality interlayer between top- and bottom-layered NCs can be formed. Owing to the ultra-thin high-quality interlayer, the IB-induced DL metal NC storage layer possesses high-efficiency as well as excellent-reliability properties simultaneously. On top of that, emerging Cu/SiOx-based ReRAMs have been investigated. Although the Cu/SiOx-based ReRAMs have many merits of process and material compatibility with the semiconductor industry, wide memory window, fast switching speed, etc., poor high-temperature retention and unacceptable switching endurance block its development. Previous reports indicated clearly that the poor reliability can be ascribed to over-high Cu concentration in active SiOx layer. In this topic, we developed an advanced Cu-doping technique based on the IB module to replace the use of Cu electrode. Using IB-induced Cu-doping technique, the Cu concentration in the active SiOx layer can be limited to further improve reliability. Compared to other Cu-doping methods, this IB-induced Cu-doping technique is more suitable to the current CMOS process, besteading the future 1T-1R integration.