Trap generation and electron detrapping in SiO2 during high-field stressing of metal-oxide-semiconductor structures

Direct evidence for electron trap generation during high-field stressing of thermally grown SiO2 layers is obtained using avalanche injection followed by internal photoemission measurements on Al-gate metal-oxide-semiconductor structures. Avalanche injection is used to fill oxide traps with a minimum risk of oxide degradation. It is shown that traps are created near the Si-SiO2 interface of a 39-nm-thick oxide on p-Si stressed in accumulation. After intentional charging the centroid of the additional charge distribution corresponding to the newly created traps is located at 5(±2.5) nm from the Si-SiO2 interface. Any bulk oxide charge is detrapped during a high-field stress. The importance of these findings in relation to breakdown in SiO2 is indicated.