A Unified Approach to the Sensitivity and Variability Physics-Based Modeling of Semiconductor Devices Operated in Dynamic Conditions. Part II—Small-Signal and Conversion Matrix Sensitivity

Abstract

We present here and in Part I a general framework for the modeling of semiconductor device variability through the physics-based analysis of the small-change sensitivity. While Part I focuses on the sensitivity of the device terminal currents in periodic large-signal (LS) operation, we extend here the analysis to the linearized device representations, i.e., to the sensitivity of the small-signal (SS) admittance matrix (SS sensitivity) and the conversion admittance matrix (SS-LS sensitivity). The proposed technique is based on the linearization of a physical device model around a nominal process parameter, and on the evaluation of relevant Green’s functions linking the parameter variations to the terminal performance. This provides, for the first time, a unified and computationally efficient simulation framework for the device physics-based sensitivity in dc, SS, LS, and SS-LS conditions. To highlight the accuracy of the approach when compared with the incremental evaluation, we discuss two case studies, concerning the SS-LS sensitivity of a class A GaAs MESFET-based amplifier and the SS sensitivity of an AlGaN/GaN microwave HEMT.