High-k MNOS-Like Stacked Dielectrics for Non-Volatile Memory Application
Charge-trapping memories such as SONOS and MONOS have attracted considerable attention as promising alternatives for next-generation flash memories due to dielectric layer’s scalability, process simplicity, power economy, operation versatility. Nevertheless, the continued miniaturization of the devices forces an application of high-k dielectrics. In this work high-k stacked dielectric structures based on the combination of Hf-based and SiNx materials were fabricated. Their structural and electrical properties versus deposition conditions are studied by means of FTIR-ATR and high-resolution TEM techniques. All samples demonstrated smooth surface (roughness below 1 nm) and abrupt interfaces between the different stacked layers. No crystallization of Hf-based layers was observed after annealing at 800°C for 30 min, demonstrating their amorphous nature and phase stability upon annealing. Electrical characterization was carried out for all samples through capacitance-voltage (C-V) measurements of MIS capacitors. Uniform C-V characteristics were measured along the samples for all stacks. Besides, significant flat-band hysteresis due to charging of the stacks caused by carrier injection from the substrate was observed for the structures with pure HfO2 layers.
Prof. Alexei N. Nazarov, Prof. Volodymyr S. Lysenko, Prof. Denis Flandre, Dr. Yuri V. Gomeniuk
L. Khomenkova et al., "High-k MNOS-Like Stacked Dielectrics for Non-Volatile Memory Application", Journal of Nano Research, Vol. 39, pp. 121-133, 2016