Self-aligned shallow trench isolation recess effect on cell performance and reliability of 42nm NAND flash memory

Self-aligned shallow trench isolation recess effect on 42 nm node NAND flash to achieve high performance and good reliability has been studied and demonstrated. As cell STI recess is increased by 23 nm, 29% narrower cell Vth distribution width and 54% less cell Vth shift after 125°C, 2 hours can be obtained. Furthermore, the endurance window is obviously improved ~0.5V as the distance of the active area edge to control gate (CG) is increased at the same time. Deeper STI recess and enough active area edge to CG distance are a promising profile for floating gate based NAND flash at 42 nm node and beyond.