S. Takagi et A. Toriumi, QUANTITATIVE UNDERSTANDING OF INVERSION-LAYER CAPACITANCE IN SI MOSFETS, I.E.E.E. transactions on electron devices, 42(12), 1995, pp. 2125-2130
The inversion-layer capacitance (C-inv) in n-channel Si MOSFET's, is s
tudied experimentally and theoretically with emphasis on the surface c
arrier concentration (N-s) dependence of C-inv, which is important in
the quantitative description of the inversion-layer capacitance, Based
on the experimental N-s and temperature dependencies, the physical or
igin of C-inv is discussed, It is shown that, at lower N-s, C-inv is d
etermined by the finite effective density of states, while, at higher
N-s, C-inv is determined quantum mechanically by the finite inversion-
layer thickness, Also, the results of the surface orientation dependen
ce of C-inv are presented as the first direct evidence for the fact th
at surface quantization plays a significant role in C-inv even at room
temperature, The self-consistent Poisson-Schrodinger calculation of C
-inv is performed and found to represent the experimental results accu
rately, The influence of C-inv on the gate capacitance is discussed in
terms of the device scaling on basis of the experimental and calculat
ed values of C-inv.