Investigating Quasi-Nonvolatile Memory Behavior in Junctionless Field-Effect Transistors with SOI-Like Structure

This study presents a junctionless FinFET based quasi-nonvolatile memory (JL-FinFET QNVM) device with a silicon-on-insulator-like (SOI-like) structure and long retention time. In the JL-FinFET QNVM, the weak impact ionization mechanism is used to appropriately a induce weak impact ionization during the hold operation to generate holes continuously; this prevents the recombination of holes in the hold time. The sensing margin at both 300 and 358 K was 3.33 μA/μm when using the weak impact ionization mechanism in the proposed transistor. In particular, the proposed device showed an exceptionally lengthy retention time, with the quasi-nonvolatile characteristics exceeding 10² s regardless of the temperature. Additionally, the reliability of the proposed device was simulated by considering the grain boundary variation in polycrystalline silicon that was used for the SOI-like structure. The Shockley–Read–Hall recombination, hole density, and electron potential barrier were also analyzed to explore the memory state during the weak impact ionization mechanism.