High-performance non-volatile CdS nanobelt-based floating nanodot gate memory

Abstract

High-performance, non-volatile, floating nanodot gate memories (FNGMs) based on single CdS nanobelts (NBs) are reported. Their structure consists of a CdS NB field-effect transistor and Au nanodots embedded in high-κ HfO₂ top-gate dielectrics. Direct tunnelling of charges between the CdS NB and the Au nanodots causes a shift of the threshold. A simple thermal evaporation method was employed to fabricate high-density, uniformly distributed Au nanodots (∼3 × 10¹² cm⁻²) in between a 5 nm HfO₂ tunnelling layer and a 15 nm HfO₂ control oxide layer. Under a low operation voltage of 5 V, a typical as-fabricated FNGM has a large memory window of 3.2 V, long retention time of up to 10⁵ s, and good stress endurance of more than 10⁴ write/erase cycles. The working principle of the CdS nanobelt-based FNGM is discussed in detail in this paper.