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

Abstract

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.