Experimental analysis of on-wafer de-embedding techniques for RF modeling of advanced RFCMOS and BiCMOS technologies

Based on hardware measurement of 45nm RFCMOS and 130nm SiGe BiCMOS wafers, we present the first experimental investigation of the accuracy of various de-embedding techniques for high-frequency (up to 110GHz) on-wafer s-parameter characterization. The results clearly show that 4-port COMPLETE de-embedding offers accurate results only if the non-ideality of resistor standards is properly taken into account by using a newly developed technique. The industry-standard open-short (OS) de-embedding causes error at frequencies above 30GHz, and the pad-open-short technique significantly improves de-embedding accuracy over OS and, therefore, becomes an attractive approach since it only requires one more test structure than OS. The effects of gate electrostatic-discharge protection diodes on de-embedding accuracy for RFCMOS FETs are also presented and a technique is proposed that minimizes the associated errors.