A gate-all-around polycrystalline silicon nanowire (NW) floating-gate (FG) memory device was fabricated and characterized in this work. The cross-section of the NW channels was intentionally made to be triangular in shape in order to study the effects of the corners on the device operation. Our results indicate that the channel corners are effective in lowering the programming and erasing (P/E) operation voltages. As compared with the charge-trapping type devices, a larger memory window is obtained with the FG scheme under low-voltage P/E conditions. A model considering the nature of the charge storage medium is proposed to explain the above findings.

Gate-all-around (GAA) nanowire (NW) memory devices with a SiN-or Hf-based charge-trapping (CT) layer of the same thickness were studied in this work. The GAA NW devices were fabricated with planar thin-film transistors (TFTs) on the same substrate using a novel scheme without resorting to the use of advanced lithographic tools. Owing to their higher dielectric constant, the GAA NW devices with a HfO 2 or HfAlO CT layer show greatly enhanced programming/erasing (P/E) efficiency as compared with those with a SiN CT layer. Furthermore, the incorporation of Al into the Hf-based dielectric increases the thermal stability of the CT layer, improving retention and endurance characteristics.

In this work, we have successfully demonstrated the feasibility of a method, which relies solely on I-line-based lithography, for fabricating sub-100 nm tri-gated junctionless (JL) poly-Si nanowire (NW) transistors. This method employs sidewall spacer etching and photoresist (PR) trimming techniques to shrink the channel length and width, respectively. With this approach, channel length and width down to 90 and 93 nm, respectively, are achieved in this work. The fabricated devices exhibit superior device characteristics with low subthreshold swing of 285 mV/dec and on/off current ratio larger than 10 7 .

A novel gate-all-around (GAA) poly-Si floating-gate (FG) memory device with triangular nanowire (NW) channels was fabricated and characterized in this work. The enhanced electric field around the corners of the NW channels boosts more electrons tunneling through the tunnel oxide layer during programming and erasing (P/E) processes, and thus the operation voltage markedly decreases. Furthermore, the nonlocalized trapping feature characteristic of the FG makes the injection of electrons easier during the programming operation, which was demonstrated by technology computer-aided design (TCAD) simulations.

A method for fabrication of tri-gate polycrystalline silicon (poly-Si) transistors with short channel length and width is proposed and demonstrated without employing costly lithographic tools. Specifically, the method employs a spacer formation technique to extend source and drain regions so as to scale down the channel length below sub-lithographic dimension. Concurrently, the channel width is scaled down below sub-lithographic dimension by using a photoresist (PR) trimming technique. Our results show that the reduction in the planar channel width is essential for suppressing the short-channel effects. Finally, devices with channel length of 120 nm and planar channel width of 110 nm are demonstrated with superior electrical characteristics in terms of small subthreshold swing (146 mV/dec) and low drain-induced-barrierlowing value (100 mV/V).