Abstract
Structures of SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> have been prepared on Si wafers by ion beam sputtering deposition in ultrahigh vacuum (UHV) and subsequently annealed to form single-layer and doubly stacked Si nanocrystals (NCs). Using these two structures, nonvolatile Si-NC floating-gate nMOSFETs were fabricated at x=1.6 following 1.5-mum CMOS standard procedures. The Fowler-Nordheim tunneling of the electrons through the tunnel oxide, their storage into NCs, retention, and endurance are all investigated by varying the device structure and the thicknesses of the NC and oxide layers. It is shown that charge-retention time is longer, and program/erase (P/E) speeds are faster in doubly stacked devices than in single-layer devices, which seem to result from the optimization of device structure, the exclusion of unwanted defects due to the nature of UHV, and the suppression of charge leakage by the multiple barriers/NC layers in the doubly stacked devices. It is also found that the threshold voltages in the endurance characteristics anomalously increase with the P/E cycles, more strongly in the doubly stacked NC memories
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
