High performance nonvolatile memory using SiO₂/SiO _x/SiO_xN_y stack on excimer laser-annealed polysilicon and the effect of blocking thickness on operation voltage

Silicon-rich SiO_x material is a good charge storage candidate for memory applications that promise a large memory window and low operation voltage. Nonvolatile memory (NVM) devices fabricated on excimer laser-annealed polysilicon using SiO₂/SiO_x/SiO_xN_y (OOxOn) structure are investigated with SiO₂ blocking thicknesses changing from 15 to 20 to 30 nm. The Si-rich SiO_x material exposed numerous non-bridging oxygen hole-centre defect sources and a rich silicon phase in the base material. These defects, as well as amorphous silicon clusters existing in the SiO_x layer, enhance the charge storage capacity of the device. Retention properties were ensured by 3.2 nm SiO_xN _y tunnelling layer growth via N₂O plasma-assisted oxynitridation. NVM characteristics showed a retention exceeding 85% of the threshold voltage shift after 10⁴ s and greater than 70% after 10 years. Depending on the blocking thickness of 15, 20 or 30 nm, operating voltages varied from ±9 to ±13 V at a programming/erasing duration of only 1 ms. These excellent operating properties of the OOxOn structure make it a potential competitor among the new generation of memory structures on glass.