Analysis, Formulation, and Implementation of a Nonlinear Equivalent Circuit for High-Frequency Semiconductor Diodes

In this work, a modeling methodology is proposed for building up a quasi-analytical equivalent circuit of semiconductor diodes. In particular, it is demonstrated how this nonlinear intrinsic model can be directly extracted from port current and voltage waveform responses under single-tone injections through a formulation which relates the spectral coefficients of the state-functions involved. The extraction technique also includes a multi-bias S-parameters-based flow for characterizing the extrinsic linear network whose proper estimation is essential in high-frequency applications. Another strength of the proposed solution is that the quasi-static version can be extended to a first-order nonquasi-static approach for the modeling of typical relaxation times in high-frequency electron devices. These models have been analytically formulated and implemented in a Computer-Aided Design tool for a commercial Schottky diode and a varactor. Experimental tests for both devices at microwave frequencies prove how the nonquasi-static equivalent diode successfully responds when frequency grows up. In addition, the extracted circuits are able to extrapolate in frequency under several bias and power conditions. This strategy provides a solution to overcome some foundry models' limitations under modern power and frequency operating conditions and enhances reconfigurable prototypes design.