Analysis of Random Telegraph Noise Characteristics with Two Different Cell States in 3-D NAND Flash Memory
Nagyong Choi, Ho-Jung Kang, Jong-Ho Lee · JSTS Journal of Semiconductor Technology and Science · 2019
The random telegraph noise (RTN) properties in two different cell states in 3-D NAND flash memory with a tube-type poly-Si body are analyzed. We analyze the fluctuation in bit-line current (ΔISUBBL/SUB) with increasing ISUBBL/SUB and the low frequency noise characteristics in the erase (ERS) and the program (PGM) cell states. It is found that the ISUBBL/SUB fluctuation by the RTN is more influenced in the ERS state than that in the PGM state at low ISUBBL/SUB condition. Simulated electron concentration in channel at low ISUBBL/SUB of the cell in PGM state shows that electrons are distributed below the interface between tunneling oxide and poly-Si body due to the repulsive force between electrons in channel and the nitride storage layer. Since the channel of the cell in the PGM state is located relatively distant from the trap causing the RTN, noise power spectral density in low ISUBBL/SUB of the PGM state is smaller than that of the ERS state.