A General Dimension Reduction Method for the Dispersion Modeling of Semiconductor Devices

This paper presents a general dimension reduction method for the dispersion modeling of current and charge sources of semiconductor devices including HEMTs, LDMOS, and HBTs. The dimensions that are easily handled are represented by the existing empirical or physical functions, while those dimensions that are difficult to tackle with or have limited measurement data are represented by the Taylor expansion. In this paper, an AlGaN/GaN HEMT was taken as the example device to illustrate how this method can be applied to handle the comprehensive dispersion effects induced by thermal and charge trapping. The dimensions of terminal voltages (V-gs, V-ds) are characterized by the 10-parameter Angelov function, while the remaining dispersion-related dimensions (channel temperature T-j and drain trap state phi(D)) are expressed by the Taylor expansion. The constructed drain current source (I-ds) model is able to predict a number of pulsed I-Vs with various channel temperature and quiescent biases. Finally, the analytical large signal model was implemented in the advanced design system, and several RC sub-circuits with multiple time constants were exploited to implement the dispersion model in the simulator. Good agreement has been achieved for both small-signal and large-signal characteristics of the investigated devices.