Impact of band structure on charge trapping in thin SiO/sub 2//Al/sub 2/O/sub 3//poly-Si gate stacks

Electron and hole trapping were studied in sub-2-nm SiO/sub 2//Al/sub 2/O/sub 3//poly-Si gate stacks. It was found that during substrate injection, electron trapping is the dominant mechanism. Conversely, during gate injection both hole and electron trapping can be observed, depending on the applied bias. These hot carrier effects are closely linked to the band structure of SiO/sub 2//Al/sub 2/O/sub 3//poly-Si system.