Evaluation Technique for Soft-Error Rate in Terrestrial Environment Utilizing Low-Energy Neutron Irradiation

Technology scaling of semiconductor devices improves circuit performance but at the same time degrades a radiation-induced soft-error tolerance. The measurement of soft-error tolerance of devices is one of key technologies to guarantee quality reliability. The conventional measurement methods require high-energy neutron beam. In this paper, we propose a method to measure soft-error rate in terrestrial environment irradiating with a low-energy neutron beam. Our proposed method requires low-energy neutron beam whose energy is less than 40MeV and the measurement cost can be reduced comparing the conventional methods. Our proposed method is applied to FPGAs fabricated in 90nm, 65nm, 40nm, and 28nm processes, and results of our proposed method are compared with those of conventional methods. The comparison results shows the accuracy of our proposed method is comparable with that of conventional ones for the CRAMs of FPGAs fabricated in processes less than 40nm. Therefore, measurement cost reduction can be achieved with our proposed low-energy neutron method.