Effects of Poly-Si Grain Boundary on Retention Characteristics under Cross-Temperature Conditions in 3-D NAND Flash
Ukju An1, Gilsang Yoon1, Donghyun Go1
1Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.
Abstract:
Electrical characteristics with various program temperatures (T) in three-dimensional (3-D) NAND flash memory are investigated. The cross-temperature conditions of the T up to 120 °C and the read temperature (T) at 30 °C are used to analyze the influence of grain boundaries (GB) on the bit line current (I) and threshold voltage (V). The V shift in the E-P-E pattern is successfully decomposed into the charge loss (ΔV) component and the poly-Si GB (ΔV) component. The extracted ΔV increases at higher T due to the reduced GB potential barrier. Additionally, the ΔV is evaluated using the Technology Computer Aided Design (TCAD) simulation, depending on the GB position (X) and the bit line voltage (V).


