Nitrided Tetragonal $\hbox {ZrO}_{2}$ as the Charge-Trapping Layer for Nonvolatile Memory Application

Employment of a tetragonal ZrO₂ film as the charge-trapping layer for nonvolatile memory was investigated and the NH₃ nitridation effect of the ZrO₂ film on memory performance was also explored in this letter. The permittivity of the tetragonal ZrO₂ film is slightly reduced from 38.7 to 36.9 after nitridation; nevertheless, nitridation introduces more trapping sites and passivates the grain boundary channel which results in a high operation speed in terms of 2.6-V flatband voltage shift by programming at +10 V for 10 ms and a good retention characteristic with 20.2% charge loss after ten-year operation at 125degC, both are superior to that without NH₃ nitridation. Most importantly, the process is fully compatible with existent ULSI technology and paves the way to adopt a high-permittivity crystalline dielectric as the charge-trapping layer for future high-performance nonvolatile memory.