Micron developed a floating gate type memory cell up to 3rd generation 3D NAND flash memory, but from 4th generation it changes to charge trap method.
Charge traps are being used by Samsung, Toshiba (WDC) and SK Hynix. Intel is continuing to use floating gate which is better for high endurance products needed in a data center.
The charge trap approach seems to be better suited to manufacturing based on the success of the existing manufacturers. Its also easier to manufacture charge traps as they are very simple cells to design.
Given the low average selling prices the charge trap is the lowest cost way to develop NAND. Cost savings are more important than TBW life. generally most SSD drives do not experience very much writing aside from the Windows Swap file.
Wear levelling has done much to add years to SSD life so a slight reduction in endurance is not a major concern.
Micron’s fourth-generation NAND flash memory offers 30% more write throughput than the third generation and 40% less energy for 1-bit recording. Its expected that it can be stacked up to 128 layers as well.