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 article, we evaluate the impact of X-ray effects on the alpha-induced soft error rate in 3-D nand flash memories with replacement gate (RG) architecture, one of the most widely used non-volatile technologies. 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.