Impact of Mechanical Stress on the Electrical Performance of 3D NAND.

We have developed a methodology for analyzing the impact of mechanical stress on the electrical performance of 3D NAND devices. The methodology relies on in-situ electrical characterization of 3D NAND flash memory under application of an external load with a nanoindenter. The forces applied in the experiment are converted to stress using finite element modeling and the obtained values are correlated with electrical characteristics. With this method, I ON and I OFF degradation with compressive stress along the memory channel is demonstrated and compared for three types of channel materials: polysilicon full channel, single crystal silicon full channel, and polysilicon macaroni channel. TCAD simulations attribute the changes in I ON and I OFF to mobility decrease and Shockley-Read-Hall generation rate increase under stress, respectively.