Temperature dependence of the relaxation of injected charge at the polycrystalline-silicon-SiO₂ interface

Abstract

Electron injection can occur at the polycrystalline-silicon-SiO2 interface of a polycrystalline-silicon gate MOS capacitor when relatively low negative voltages are applied to the gate. If the interface is improperly annealed, the flat-band shift due to injected electrons can be several hundred millivolts for 350-Å-thick oxides. The temperature and voltage dependence of the relaxation of injected negative charge has been measured. The amount of charge injected is higher and its relaxation is faster at higher temperatures. The moment of charge can shift towards the substrate silicon-SiO2 interface at negative gate voltages whose absolute magnitudes are less than the flat-band voltage of the capacitor.