Channel Coupling phenomenon as scaling barrier of NAND flash memory beyond 20nm node

A new program disturbance phenomenon appeared from sub 40nm-node NAND flash cell is presented firstly which is named as BTBT Leakage Burst by Channel Coupling (abbr. “Channel Coupling”). With scaling down, the neighboring program channel of 0V grabs strongly the boosted channel at program-inhibited active line not to rise up at the active sidewall and simultaneously, its potential at Si surface is tried to be raised by help of pass voltage. The competition induces the sharp bandbending and thereby sudden enhancement of BTBT leakage, resulting in suppressing channel boosting. In order to overcome “Channel Coupling” appeared at 1X-nm node as a scaling barrier, the air gap in shallow trench isolation is suggested and the effect of the air gap is verified by simulation.