Thin oxide thickness extrapolation from capacitance-voltagemeasurements

Five oxide-thickness extrapolation algorithms, all based on the same model (metal gate, negligible interface traps, no quantum effects), are compared to determine their accuracy. Three sets of parameters are used: (acceptor impurity concentration, oxide thickness, and temperature): (10¹⁶ cm^-3, 250 Å, 300 K), (5×10¹⁷ Cm^-3, 250 Å, 300 K), and (5×10¹⁷ cm^-3, 50 Å, 150 K). Demonstration examples show that a new extrapolation method, which includes Fermi-Dirac statistics, gives the most accurate results, while the widely-used C_o≃C_g (measured at the power supply voltage) is the least accurate. The effect of polycrystalline silicon gate is also illustrated