The effects of x-ray irradiation on the reliability of n-channel MOSFET's with 10nm gate oxides are reported as a function of dose (1. 5 multiplied by 10**6 and 1. 5 multiplied by 10**7 rads) and temperature (300K and 77K). The dominant channel hot-carrier degradation appears to be due to interface-state generation instead of bulk oxide traps, independent of x-ray irradiation. The density of residual positive traps must be reduced to minimize channel-hot-electron induced threshold voltage shift. The residual neutral traps after x-ray exposure and 400C forming-gas anneal do not reduce the device lifetime under worst-case channel hot-carrier stress conditions. In this respect, less sensitive resists may be used for x-ray lithography processes.