Interstitial filling induced local charge enhancement boosts the electron shielding efficiency of high-entropy alloys used to packaging hardening MOSFETs

The development of anti-irradiation packaging hardening high-entropy alloy (HEA) materials is critical for enabling the aerospace application of commercial devices. However, the interstitial structures formed by atomic stacking within the material remain weak points for radiation degradation. Here, carbon was introduced into the Cr₁₂Nb₂₂Mo₂₂Ta₂₂W₂₂ by high-energy ball-milling, successfully filling the geometric interstitial in atomic stacking. DFT calculations further revealed that the interstitial filling effect induces significant charge accumulation around carbon atoms. The increased local electron density enhances the probability of inelastic collisions, improving the attenuation capability of the packaging material against incident electrons. Experimental results demonstrate that the C_4[sbnd]HEA/EP exhibits a 10.43 % enhancement in radiation shielding efficiency for 1 MeV electrons compared to the C_0[sbnd]HEA/EP composite, achieving 2.64 times of aluminum sheet. Moreover, packaged MOSFETs display exceptional irradiation stability. This "interstitial filling" effect provides novel strategy for developing packaging materials, significantly advancing the potential of commercial devices in aerospace applications.