Reduction of α-particle sensitivity in dynamic semiconductor memories (16K d-RAMs) by neutron irradiation

Trace radioactive impurities found in all semiconductor devices induce soft errors in semiconductor memories by α-particle emission. Data taken on 16K d-RAMs which have been fast neutron irradiated to fluences from 10¹³ to 10¹⁶ n/cm² show that soft errors in these devices can be significantly reduced while maintaining acceptable device operation. Reduction in soft error rate by factors as high as 80 are observed following irradiation and thermal annealing. The effect on device parameters is discussed as well as the defects responsible for this beneficial radiation processing. Estimates of the soft error rate improvement to be expected on higher density memory devices (64K and 256K d-RAMs) will also be presented.