Effectiveness of Surface Potential Fluctuation for Representing Inversion-Layer Mobility Limited by Coulomb Scattering in MOFETs

In this letter, the effectiveness of surface potential fluctuation (σ
_s
), experimentally extracted from the conductance method, in representing the mobility limited by Coulomb scattering (μ
_coulomb
) due to MOS interface charges has been experimentally examined in Si MOSFETs. It is found that μ
_coulomb
can be described as a universal line proportional to σ
_s
^-2
, irrespective of the conditions of MOS interface charges, even under the coexistence of positive and negative charges, where threshold voltage shift (ΔV
_th
) cannot represent μ
_coulomb
. This result can be explained by considering that σ
_s
²
more directly corresponds to the total amount of Coulomb scattering centers.