Accuracy of surface-potential-based long-wide-channel thick-base MOS transistor models

作者：Jie Bin B^*; Sah Chih Tang

来源：IEEE Transactions on Electron Devices, 2007, 54(8): 1897-1909.

DOI：10.1109/TED.2007.900674

• baseline model
• bulk-charge approximation
• four-component space-charge theory
• MOSFET
• MOST
• self-consistent remote charge boundary condition
• surface potential model

This paper answers the frequently asked question, "How accurate are the approximate long-wide-channel thickbase MOS transistor baseline models that have been used to develop the compact models for computer-aided circuit designs?" Three commonly used surface-potential-based (U-s = q psi(s) / kappa T) approximations of the ionized impurity bulk charge are evaluated as follows: Q(B) proportional to (i) (U-S)(1/2); (ii) (U-S - 1)(1/ 2); (iii) [U-s - 1 + exp(- U-s)(1/2). The double-integral baseline model for comparison includes the self-consistent remote charge-neutrality boundary condition, minority carriers, and spaceconstant impurity-concentration and oxide thickness. Percentage deviations of the approximations from the baseline model are computed for the dc drain current. Approximation (i) show a significant deviation, which is similar to 16% at threshold voltage, diverging rapidly in the subthreshold range toward flatband. Approximations (ii) and (iii) show a few percent (1 % to 2 %) deviations in both inversion and subthreshold ranges but diverge widely below subthreshold and in accummulation. A new analytical model is tested and shows better than 10% accuracy below subthreshold and in accummulation.

• 出版日期2007-8
• 单位北京大学