Analysis of Program Disturbance Immunity of VA-SGLC Embedded Nonvolatile Memory

We have analyzed the program disturbance immunity mechanism of a vertical assist-select gate lateral coupling (VA-SGLC) cell. Comparing different operation methods of unit cells fabricated with the same process, we verified the array structure and operation mode dependence of the program disturbance. As an embedded nonvolatile memory, the VA-SGLC cell offers advantages of no additional masks and process steps as well as fast program speed and program/erase cycling performance exceeding 10 k. Furthermore, it exhibited abnormally strong disturbance immunity. Using worst-case disturbance measurements and potential difference comparisons, we verified the mechanism of the abnormally strong disturbance immunity of the VA-SGLC cell. The strong program disturbance immunity of VA-SGLC cell is due to the varying coupling ratio caused by coupling dividing operation methods. These features arise from the distinctive array structures and operation methods of the VA-SGLC cell.