Charge accumulation in MOS structures with a polysilicon gate under tunnel injection

Charge accumulation in metal–oxide–semiconductor (MOS) structures with a doped and undoped polysilicon gate with Al contacts and without them under tunnel electron injection from the gate and silicon substrate is investigated. It is shown that negative charge is accumulated near the polysilicon gate irrespective of the injection polarity, and positive charge is accumulated near the silicon substrate. Negative charge also appears near the silicon substrate at large injection charges. The results are described with the help of a numerical model, in which the formation of electron traps with the deposition of Al contacts and the generation of electron traps during the recombination of free electrons with holes captured at traps is taken into account.