Silicon Ultrathin Oxide (4.2 nm)–Polysilicon Structures Resistant to Field Damages

Abstract

The results of investigations of silicon–ultrathin oxide (42 Å)–polysilicon structures resistant to field damages are presented. It is found that the total charge exchange of localized electronic states and minority charge carriers concentrated at the substrate–insulator interface, which occurs with a change in the field voltage, is close to the same characteristic of structures with an oxide thickness of 37 Å. The current flowing through SiO₂ increases with voltage much stronger in the enrichment state of the semiconductor than in its depletion state. Moreover, the asymmetry of the I–V characteristics with respect to the polarity of the voltage drop across the insulator in SiO₂ samples with a thickness of 42 Å is more pronounced than in structures with an oxide of 37 Å. An explanation for this asymmetry is possible, if the potential relief in the insulator has a peak, which is significantly shifted to the oxide–polysilicon interface, and the potential on the branch on the semiconductor side significantly decreases towards the contact with the substrate.