Synchrotron X-Ray Irradiation Effects on the Device Characteristics and the Resistance to Hot-Carrier Damage of MOSFETS with 4 nm Thick Gate Oxides

摘要

The effects of synchrotron x-ray irradiation on the device characteristics and hot- carrier resistance of n- and p-channel metal oxide semiconductor field effect transistors (MOSFETs) with 4 nm thick gate oxides are investigated. In p- channel MOSFETs, device characteristics were significantly affected by the x- ray irradiation but completely recovered after annealing, while the device characteristics in n-channel MOSFETs were not noticeably affected by the irradiation. This difference appears to be due to a difference in interface-state generation. In p-channel MOSFETs, defects caused by boron-ion penetration through the gate oxides may be sensitive to x-ray irradiation, causing the generation of many interface states. These interface states are completely eliminated after annealing in hydrogen gas. The effects of irradiation on the resistance to hot-carrier degradation in annealed 4 nm thick gate-oxide MOSFETs were negligible even at an x-ray dose of 6000 mJ/cm~2.