Lombardi's mobility model accounts for the effect of the transverse electric on mobility in a MOSFET device. Lombardi's formulation adds terms for surface acoustic phonon ( ) and surface roughness scattering ( ) to the bulk mobility ( ) using a Matthiesen-like rule:
The bulk mobility ( ) can be from a variety of formulations, typically the Arora model in Prophet. Lombardi gives the following forms for and :
Table 3 summarizes the Prophet parameter names and default values for the Lombardi mobility model. Conventional usage expresses mobility in units of ; however, Prophet uses units of , so the numerical values of the mobility parameters appear to be larger than usual.
Table 3: Lombardi Mobility Model Parameters and Default Values