Radiation hardening of dynamic memories by the use of a new dummy cell concept

The soft error rate (SER) of DRAMs with advanced structures can be reduced significantly by the use of a new dummy cell concept. Compared to conventional dummy cell concepts, this concept applies a fully sized dummy cell. By optimising the dummy cell precharge voltage and the timing for activation of the dummy word line, the overall SER of the chip is reduced by two orders of magnitude. This is because the SER sensitivity for a physical "1" is matched to the SER sensitivity for a physical "0". The results are verified by an accelerated SER measurement with a radium 226 source and an additional field soft error study.<
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