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, ION and IOFF 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 ION and IOFF to mobility decrease and Shockley-Read-Hall generation rate increase under stress, respectively.

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