IMPACT OF THE POLYSILICON DOPING LEVEL ON THE PROPERTIES OF THE SILICON OXIDE INTERFACE IN POLYSILICON/OXIDE/SILICON CAPACITOR STRUCTURES/

In this work, new observations noted in the capacitance-voltage (CV) b ehaviour of polysilicon/oxide/silicon capacitor structures are reporte d. As the doping concentration in the polysilicon layer is reduced, an omalous CV characteristics are observed, which are not related to depl etion into the polysilicon layer. By examination of the temperature an d frequency dependence of the CV characteristics, in conjunction with analysis and simulation, it is demonstrated that the anomalous CV beha viour is a result of a high density of near monoenergetic interface st ates located at the silicon/oxide interface. Furthermore, by an examin ation of the temperature and time of the final anneal (H-2 + N-2), a m echanism by which the polysilicon doping level can influence the silic on/oxide interface properties is proposed.