A low-frequency noise analysis using the two-dimensional numerical analysis method

A low-frequency (
1/f
) noise analysis is presented for a MOSFET. Poisson's equation and current continuity equation are numerically Solved to determine hole and electron concentrations in two dimensions, The Power spectrum of the fluctuation in the drain current
S_{i}_{d}
is calculated by using obtained hole and electron concentrations, current distribution, and mobility distribution, based on the number fluctuation (NF) and mobility fluctuation (MF) models. It is found, from the comparison with experiments for n- and p-channel surface mode MOSFET's, that both NF and MF models can explain noise characteristics for surface-mode MOSFET's. In the case of a depletion-mode MOSFET, the MF model shows that
S_{i}_{d}
is proportional to drain current i
d
, which is in agreement with the experimental result for a commercial depletion-mode MOSFET. However, the NF model cannot explain the
S_{i}_{d} \alpha i_{d}
characteristic.