Effect of post-oxidation anneal temperature on radiation-induced charge trapping in metal-oxide-semiconductor devices

Polycrystalline silicon-gate metal-oxide-semiconductor (MOS) capacitors have been fabricated with high-temperature anneals from 800 to 950 °C after gate oxidation and polycrystalline silicon deposition. Temperatures from 800 to 875 °C are found to have very little effect on the radiation response of these devices. However, a rapid increase in radiation-induced oxide-trapped charge, ΔVot, is observed for anneal temperatures above 875 °C. This increase in ΔVot coincides with an experimentally observed change in the polycrystalline silicon grain structure. The anneal temperature was found to have a much smaller effect on radiation-induced interface-trap charge. The correlation of these results to other properties, e.g., stress, is discussed.