Abstract
The radiation response of Al2O3 on silicon substrate under gamma-rays is studied in this article. The atomic layer deposited Al2O3 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 Al2O3 is up to 1012 cm−2, with the effective trapping efficiency of 7–20% under irradiation. Secondly, the leakage current through Al2O3 changes little with the increase of radiation total dose. Thirdly, oxygen vacancy in Al2O3 and O dangling bonds and Al-Si metallic bonds at Al2O3/Si interface are dominant radiation induced defects in Al2O3/Si system, and the valence band offset between Al2O3 and Si is found to decrease after irradiation. From the results we can see that Al2O3 is radiation resistant from the aspect of leakage current and crystallization characteristics, but the radiation induced charge trapping and new defects in Al2O3/Si structure cannot be ignored. This paper provides a reference for the space application of Al2O3 based MOS devices.
Highlights
Microelectronic technology has been developing through the ‘Moore’s Law’ for several past decades and the feature size of the transistors in devices are reducing continuously
Irradiation significantly affect affect the the Crystallization characteristic characteristic of the gate dielectric film can significantly the transistor performance, as the grain boundaries between crystal lattices can act as the charge transport transportpath pathwhich whichwould wouldraise raisethe theleakage leakage current transistors
Considering ing this, researchers always non-crystallized thin to films to be the gate dielectric to this, researchers always preferprefer non-crystallized thin films be the gate dielectric to ensure ensure lower leakage current, but it is inevitable that the crystallization phases would be lower leakage current, but it is inevitable that the crystallization phases would be generated generated post deposition thermal and treatment and beinchanged in many cases
Summary
Microelectronic technology has been developing through the ‘Moore’s Law’ for several past decades and the feature size of the transistors in devices are reducing continuously. The scaling of the microelectronic devices calls for new materials such as high-k materials for the gate dielectric and low-k materials for interconnecting technology. It demands novel structures such as fin field-effect transistor, fully depleted silicon-on-insulator transistor and two-dimensional material devices and so on. High-k materials that can be used as the gate dielectric in MOS devices must have a relatively larger bandgap to ensure large enough conduction band offset and valence band offset between the gate dielectric and the semiconductor substrate, which can restrict the charge transport and reduce the leakage current of the device. Al2 O3 has been proposed as a promising candidate to replace
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