Photoelectron Effects on the Dose Deposited in MOS Devices by Low Energy X-Ray Sources

A method for calculating electron transport in layered materials is described. It is applied to a problem of radiation damage in MOS capacitors irradiated with a Cu x-ray tube operated at 45 kV. The effects of photoelectron transport are found to be significant. A problem of energy deposition in x-ray lithography is also discussed. The dose in the SiO2 gate is found to be about equal to that in the x-ray photoresist. Electron transport effects are found to be small in this lithography problem.