Damage Effect of ALD-Al(2)O(3) Based Metal-Oxide-Semiconductor Structures under Gamma-Ray Irradiation

The radiation response of Al(2)O(3) on silicon substrate under gamma-rays is studied in this article. The atomic layer deposited Al(2)O(3) based metal-oxide-semiconductor structures were irradiated under gamma-ray with the total dose of 1.2 Mrad(Si)/2.5 Mrad(Si)/4 Mrad(Si). The generation, transportation and trapping characteristics of radiation induced charges were studied by using electronic, physical and chemical methods. Firstly, the radiation induced trapped charge density in Al(2)O(3) is up to 10(12) cm(−2), with the effective trapping efficiency of 7–20% under irradiation. Secondly, the leakage current through Al(2)O(3) changes little with the increase of radiation total dose. Thirdly, oxygen vacancy in Al(2)O(3) and O dangling bonds and Al-Si metallic bonds at Al(2)O(3)/Si interface are dominant radiation induced defects in Al(2)O(3)/Si system, and the valence band offset between Al(2)O(3) and Si is found to decrease after irradiation. From the results we can see that Al(2)O(3) is radiation resistant from the aspect of leakage current and crystallization characteristics, but the radiation induced charge trapping and new defects in Al(2)O(3)/Si structure cannot be ignored. This paper provides a reference for the space application of Al(2)O(3) based MOS devices.