Interface-trap generation modeling of Fowler–Nordheim tunnel injection into ultrathin gate oxide

Abstract

Two mechanisms for interface-trap generation during Fowler–Nordheim tunnel injection into gate oxide are confirmed by the results of experiments with changes in the interface-trap density for positive and negative gate bias injections. One mechanism is independent of gate bias polarity during injection, the other mechanism is present only in negative gate bias injection. Agreements between the measured and calculated generation cross sections for both mechanisms indicate that: (i) The first mechanism is quantitatively explained using a broken-bond model by taking account of electron heating due to an oxide field during passage through the oxide conduction band. (ii) The second mechanism is quantitatively explained using a heated electron impact model where electrons heated by the oxide field generate interface traps by directly breaking the interface weak bonds when electrons cross the interface between the SiO2 and the Si substrate.