In Depth Analysis of 3D NAND Enablers in Gate Stack Integration and Demonstration in 3D Devices

An in-depth analysis of gate stack enhancements that enable multi-Gb 3D NAND products is performed. Alternative charge trapping layer, enhanced tunnel oxide based on the VariOT concept and metal gate with Al2O3 high-k liner have been proposed and evaluated. The most promising solutions were successfully integrated in 3D devices. Integration challenges of the replacement gate approach, required to have metal gate in 3D NAND, are also analyzed and discussed in detail.