The Influence of Balanced Materials on the Total Dose Radiation Reliability of Deep Sub-Micron MOS Devices

This study employs MOS devices as test subjects, implementing buildup material configurations during irradiation testing. Through monitoring radiation-sensitive electrical parameters, we investigate the impact of buildup materials on the total dose effect of ionization in MOS structures. Experimental results demonstrate that threshold voltage degradation is significantly more pronounced when buildup materials are properly applied during irradiation. Specifically, the degradation observed with front buildup layers exceeds that achieved with backscattering plates alone. Under three test configurations: (1) combined front and back buildup materials, (2) front buildup layer only, (3) backscattering plate only, the additional threshold voltage degradation at 5 krad(Si) was measured at 15.95%, 8.38%, and 7.58% respectively. At 10 krad(Si), these values decreased to 28.76%, 20.31%, and 18.98%. These findings necessitate that radiation hardness assurance protocols incorporate device-specific buildup material thicknesses aligned with structural dimensions. This ensures the sensitive region satisfies secondary electron equilibrium conditions, guaranteeing the actual absorbed dose matches the nominal irradiation dose during testing.