Poly-Silicon Trap Position and Pass Voltage Effects on RTN Amplitude in a Vertical NAND Flash Cell String
You-Liang Chou, Tahui Wang, Mercator Lin, Yao-Wen Chang, Lenvis Liu, Shih-Cheng Huang, Wen-Jer Tsai, Tsung‐Chien Lu, K. C. Chen, Chih-Yuan Lu · IEEE Electron Device Letters · 2016
We investigate the dependence of random telegraph noise (RTN) on a poly-silicon trap position in a 3D vertical channel and charge-trapping NAND flash cell string. We characterize RTN in read current of each cell of a string at different read and pass voltages. RTN characteristics resulting from a trap in a read cell or in a pass cell are differentiated. A method to identify a poly-silicon trap position in a NAND string is proposed. We perform the 3D TCAD simulation to calculate channel electron density in a string. Measured RTN characteristics can be explained by current-path percolation and channel carrier screening effects. The distribution of RTN amplitudes in NAND strings is characterized.