A study of interface trap generation by Fowler-Nordheim and substrate-hot-carrier stresses for 4-nm thick gate oxides

The generation of interface traps by different stresses to 4-nm thick SiO₂ gate oxide is studied. Four different kinds of constant current stresses were applied. The interface-trap density (D _it) generation due to hot holes under V_G<0 Fowler-Nordheim (FN) stress was characterized using quantum-yield measurement and substrate-hot-hole (SHH) stress. The interface-trap density (D_it) generated by SHH stress increases as gate-oxide field increases. Substrate-hot-electron (SHE) stress generates much less interface-trap density (D_it) than SHH stress. It is also observed that N₂O-grown gate-oxide has smaller hole-injection probability but larger electron-injection probability than O₂-grown oxide. N₂O-grown gate oxide is shown to have less SHH stress-induced interface traps than O₂-grown oxide in p-channel metal-oxide-semiconductor field-effect transistor (MOSFET) devices