Trapped Charge Energy Distribution and Transport Behavior in SONOS Flash Cells

• Main Authors: Hsin-Kai Chiang, 江欣凱
• Other Authors: Tahui Wang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/69934359597563611598

碩士 === 國立交通大學 === 電子工程系 === 91 === This thesis will focus on the discussion of trapped charge energy distribution in nitride layer and reliability issues induced by trapped charge lateral transport in a SONOS type trapping storage cell, which include program state threshold voltage shift, second bit effect, and hard to erase effect. In this study, the SONOS cell is made of a n-channel MOSFET with an oxide-nitride-oxide gate structure. Since the program state data retention loss was found to be attributed mostly to nitride charge escape by Frenkel-Poole emission and oxide trap assisted tunneling in our previous studies, the nitride charge detrapping current will be used to profile the energy distribution of trapped charge in SiN layer. In addition, a micro-second transient measurement circuit is set up to investigate the transient effect of trapped charge lateral transport. Therefore, the reliability issues, especially the significant erase degradation effect, induced by bit-line disturb in two-bit operation are observed. As P/E cycle number increases, trapped charge lateral transport induced by bit-line disturb will be enhanced. A new program pattern can be used to reduce these effects.