Reliable Technology Evaluation of SiGe HBTs and MOSFETs: f MAX Estimation From Measured Data

Maximum oscillation frequency ( ${f}_{\textit {MAX}}$ ) of mm-wave transistors is one of the key figures of merit (FOMs) for evaluating the HF-performance of a given technology. However, accurate measurements of ${f}_{\textit {MAX}}$ are very difficult. Determination of ${f}_{\textit {MAX}}$ is significantly affected by the measurement uncertainties in the admittance ( ${y}$ ) parameters. In order to get rid of the random measurement error and to obtain a reliable and stable ${f}_{\textit {MAX}}$ value, the frequency dependent ${y}$ -parameters are described by rational functions formulated from the small-signal hybrid ${\pi }$ -model of the transistor under investigation. The parameters of these functions are determined following a least square error technique that minimizes the functional error with the measured data. The approach is especially useful for a fast and reliable evaluation of ${f}_{\textit {MAX}}$ value. Devices from two different SiGe and an FDSOI (Fully Depleted Silicon On Insulator) MOS technology are measured and stable ${f}_{\textit {MAX}}$ values are estimated following this approach.