Gamma-ray irradiation-induced oxidation and disproportionation at the amorphous SiO2/Si interfaces

Abstract

The performance of Gamma-ray irradiated silicon devices usually deteriorates due to the total ionizing dose (TID) effect. The common belief is that the TID mainly involves the change of charge states of existing point defects or defect complexes and their subsequent evolution, especially at the widely used amorphous SiO₂(a-SiO₂)/Si interface, but the TID is not expected to induce new structural defects and change the interface structures. We show in this paper that, contrary to the common belief, gamma-ray irradiation can lead to remarkable structural changes characterized by oxidation and disproportionation of the a-SiO₂/Si interface. We present both experimental evidence and theoretical verification of the structural changes. The effective modulation of interfacial structures further suggests the “defective” gamma-ray to be a “constructive” defect engineering method by post-synthesis tuning of the physical performance.