Reduction of electron trapping in silicon dioxide by highhyphen;temperature nitrogen anneal

摘要

Electron trapping in silicon dioxide is reduced by nitrogen annealing in a furnace system with very low moisture content and special cooling techniques. The flatband voltage shift resulting from injected hot electrons is significantly reduced by the annealing together with the interface states generated. The trapped charge is laterally nonuniform when the oxide is not annealed. From photoIhyphen;Vmeasurement, the density of electrons trapped in the bulk of the oxide is reduced by this treatment. The distribution of the trapped charge changes from a uniform distribution in the bulk for a 1hyphen;h anneal to a distorted U shape distribution, with a larger buildhyphen;up on the aluminumhyphen;silicon dioxide side for a 17hyphen;h anneal. The density of trapped charge close to the siliconhyphen;silicon dioxide interface is reduced and thus the smaller flatband voltage shift. With the reduction in bulk change, interface state charge beomes important.