High-performance double-layer nickel Nanocrystal memory by ion bombardment technique

A novel ion bombardment (IB) technique is presented to fabricate and embed double-layer (DL) Ni nanocrystal (NC) in silicon nitride for {\rm TaN}/{\rm Al}-{2}{\rm O}-{3}/{\rm Si}-{3}{\rm N}-{4}/{\rm SiO}-{2}/{\rm Si} nonvolatile memory applications. In contrast to other methods of forming DL metal NC, the IB technique is a relatively simple fabrication method and completely compatible with the current IC manufacturing technologies. Using the IB technique, a high-quality ultrathin interlayer between top and bottom layered NCs can be easily formed and controlled. Compared with the control sample, the IB-induced DL Ni NC memory exhibits superior performance in terms of faster program and erase (P/E) speeds, longer data retention, better endurance, negligible program disturbance, and great potential for a multilevel operation. In addition, the IB-induced DL Ni NC device also shows higher P/E efficiency as well as similar excellent reliability by comparison with other conventional DL metal NC memories due to the high-quality ultrathin interlayer.