Radiation effects from a synchroton x-ray lithography source on the performance degradation and long term reliability of high performance self-aligned bipolar devices and deep sub-micron CMOS devices are studied. The hot-carrier properties of the x-ray induced damage in CMOS devices, such as interface states, positive oxide charges and neutral traps have been examined. The effect of these radiation induced defects and their impact on the DRAM circuits in terms of the performance and reliability are discussed. In the self-aligned, double polysilicon bipolar transistor structure interface states and trapped charges can be generated by the radiation source in the sidewall oxide near the emitter-base junction such damage can increase the emitter-base leakage current. This increase of base current can substantially degrade the device current gain at low bias. © 1992 TMS.