The evaluation of four CMOS models at radio frequencies

The RF simulation properties of four mainstream CMOS models were evaluated: Level 3 [1], EKV [2], Philips MOS Model 9 [3], BSIM3v3 [4]. The goal has b een to compare the RF properties of these four models. Level 3 model was ma inly chosen to be a reference. Frequencies of interest range from 300 MHz t o 10 GHz. In order to get more realistic AC results a gate resistor was add ed to EKV,MOS Model 9 and BSIM3v3. Also non-aquasi-static (NQS) operation h as been considered for BSIM3v3. The work has been done by extracting model parameters for each model. Extraction has been done by fitting simulated re sults to measured ones. 18 RF test transistors with varying widths, lengths down to 0.4 mu m and a number of parallel devices were processed in VTT Bi CMOS technology. Additional 12 test transistors were needed for DC measurem ents. General optimization algorithms and sequential extraction steps have been used in the fitting. All extractions have been done by using the APLAC circuit simulator [5] and by programs [6] written in APLAC description lan ; guage. The MOS transistor was studied as a two-port shown in Pig. 1.