Modeling the MOSFET's Inversion Layer and Its Universal Mobility: A New Experimental Method
preprintposted on 29.12.2021, 03:44 by F. ShoucairF. Shoucair
We formulate a simple, yet accurate, model for a non-uniform mobile charge density ρ(z) giving rise to a mean potential Ψ* across an inversion layer of finite extent, which we measure by means of a novel, sensitive, experimental method involving nulls of harmonic distortion components (D2 ≈ D3 ≈ 0) of the drain current under sinusoidal excitation below saturation. We thus establish analytically and experimentally, that the low-field, "universal" effective mobility µeff varies as ~(E*T)-1/3 for transversal fields ET*= -(1/εsi)·[ɳQi + Qb] ≤ 0.5 MV/cm, wherein ɳ varies continuously between 1/2 and 1/3. We also establish and observe that the higher order, derivative, parameter θT quantifying µeff’s modulation by E*T varies as ~(E*T)-5/3 under laminar flow conditions, thereby further corroborating the foregoing effects and interpretations thereof.