Memory stacks for charge trapping cells have been produced exploiting Al-doped HfO2, Al2O3, and SiO2 made by atomic layer deposition. The fabricated stacks show superior stability and electrical characteristics, allowing for the engineering of sub-1 nm equivalent oxide thickness Al doped HfO2 trapping layer with excellent retention characteristics, also at high temperature. The low Al doping content (4.5%) used in this work leads to the HfO2 crystallization, upon thermal annealing, in the cubic/tetragonal phase with a dielectric constant value of 32. The trapping properties of the proposed stacks have been studied by means of physics-based models, highlighting the role of the different layers and the nature of the traps contributing to the charge storage in the memory stack.
American Chemical Society
30 Aug 2018
Volume: 1 Issue: 9 Pages: 4633-4641
ACS Applied Nano Materials