Determination of tunnel mass and physical thickness of gate oxide including poly-Si/SiO2 and Si/SiO2 interfacial transition Layers

By including poly-Si/SiO₂ and Si/SiO₂ interfacial transition (IFT) layers, an excellent agreement in terms of both C-V and J-V characteristics is obtained between the experiment and theory for both polarities of gate voltage (V_G) for the first time. The highly precise physical models for gate depletion and gate accumulation bring an oxide thickness extracted from the C-V fitting in a negative V_G close to that extracted in a positive V_G. It is shown that the physical oxide thickness should be regarded as a distance between the middle points inside the IFT layers in both sides of the gate oxide. In addition, it is found that the tunnel mass is independent of the gate-oxide thickness from 14 to 28 Å. It is also shown that the oxide-thickness dependence of the tunnel mass , is ascribable to the C-V-J-V fitting only in the case of a negative polarity of V_G while neglecting the poly-Si/SiO₂ IFT layer.