X-Ray Effects on Alpha-Induced Soft Error Rate in 3-D NAND Replacement Gate Flash Memory Cells

In real-life operation, electronic devices are exposed at the same time to different sources of ionizing radiation. In this paper, we evaluate the impact of x-rays effects on the alpha-induced soft error rate in 3D NAND Flash memories with replacement gate architecture, one of the most widely used non-volatile technology. Threshold voltage shifts and bit error rates due to alpha particle exposure in devices previously exposed or not to x-rays are studied, focusing on the response of memory cells. Experimental results show that the alpha soft error rate is not significantly affected by previous x-ray irradiation, at least for small doses, well above those commonly used for printed circuit board inspections.