Characterization and modelling of carrier distribution and gate capacitance in MOS structure inversion layer

Based on the carrier distribution in three-dimensional semi-classical and t wo-dimensional quantum mechanical cases, the concept of surface layer effec tive density-of-states (SLEDOS) is proposed. Then a simplified method of ca lculating the band bending and subband energies is employed to investigate quantum mechanical effects (QMEs) in MOS structure inversion layer. The met hod is unique compared with published methods in its reversed nature of the iteration procedure. It has high efficiency and good convergence character istics and gives satisfactorily coincident results with rigorous but more c omplicated self-consistent calculations. The method is applicable in both q uantum mechanical and semi-classical cases. The subband occupation of inver sion layer carrier and the two-dimensional density-of-states in semi-classi cal and quantum mechanical cases are then calculated. QMEs on inversion lay er carrier density and surface potential are analysed on the basis of the m ethod. Gate capacitance in the MOS structure inversion region is formulated for both quantum mechanical and semiclassical cases, and QMEs on gate capa citance are analysed.