The evaluation of four CMOS models at radio frequencies

The RF simulation properties of four mainstream CMOS models were evaluated: Level 3, EKV, Philips MOS Model 9, BSIM3v3. The goal has been to compare the RF properties of these four models. Level 3 model was mainly chosen to be a reference. Frequencies of interest range from 300 MHz to 10 GHz. In order to get more realistic AC results a gate resistor was added to EKV, MOS Model 9 and BSIM3v3. Also non-quasi-static (NQS) operation has been considered for BSIM3v3.The work has been done by extracting model parameters for each model. Extraction has been done by fitting simulated results to measured ones. 18 RF test transistors with varying widths, lengths down to 0.4 µm and a number of parallel devices were processed in VTT BiCMOS technology. Additional 12 test transistors were needed for DC measurements. General optimization algorithms and sequential extraction steps have been used in the fitting. All extractions have been done by using the APLAC circuit simulator and by programs written in APLAC description language. The MOS transistor was studied as a two-port shown in Fig. 1 (see pdf for image)