Andrej Rumiantsev

Comparison of on-wafer multiline TRL and LRM+ calibrations for RF CMOS applications

This paper presents a quantitative comparison of the reference multiline TRL and LRM+ for a customized set of standards in a CMOS process using IBMs 0.13 mum technology. This comparison was undertaken for the first time and covered a frequency range from 1 to 110 GHz. It was demonstrated that the accuracy of the on-wafer multiline TRL and LRM+ calibration were in very good agreement. Both methods outperform the conventional off-wafer calibration with the DUT contact pad parasitics de-embedded.

Verification of the wafer-level LRM+ calibration technique for GaAs applications up to 110 GHz

In this article the accuracy of the LRM+ calibration is compared to that of the benchmark NIST multiline TRL procedure for the first time. The comparison is performed on NIST verified GaAs coplanar waveguide calibration reference material 8130. The NIST calibration comparison method is used to quantify the difference between measured S-parameters corrected by NIST multiline TRL and an advanced LRM+ calibration. The worst-case error bounds for LRM+ corrected S-parameter measurements are determined up to 110 GHz. It is demonstrated that the difference between benchmark multiline TRL and LRM+ is comparable with the measurement system drift. Verification results prove that LRM+ can be successfully used for accurate GaAs on-wafer calibration with customized standards. This overcomes some drawbacks of multiline TRL while providing the same calibration accuracy.

Applying the calibration comparison technique for verification of transmission line standards on silicon up to 110 GHz

This paper will present the results of extracting the electrical characteristics of planar lines using the calibration comparison method for standards realized in IBMs advanced 0.13 µm CMOS process. For the first time, this method is applied to characterizing the customized standards on silicon up to 110 GHz. Additionally, this paper considers the influences of the reference benchmark calibration standards, included with GaAs reference material RM8130, on the characterization accuracy of silicon wafer-embedded lines at mm-wave frequencies.

Advanced technique for broadband on-wafer rf device characterization

A technique for a broadband 2-port on-wafer RF device characterization is presented. It utilizes advanced LRM+ calibration with standards realized on a Si wafer. The approach relies on three standards: a non-perfect Thru standard, a reflection standard which is symmetrical for both ports and a complex match (Load) standard which can be different for both ports. Models for such kind of standards as well as LRM+ calibration are not supported by currently available VNA firmware. The presented method allows to set up a planar customized calibration kit (e.g. on a Si wafer) which has the same contact pad design as used for an on-wafer DUT. A simple procedure to compensate different DC resistances of port-to-port and set-to-set variation for on-wafer realized Load standards is shown. Additional wafer embedded verification elements as well as real DUT measurement results were used to compare the accuracy of the new method with the state of the art calibration and de-embedding procedure. A good calibration accuracy and significant simplification of RF device characterization procedure has been achieved with the proposed approach.

Estimation of complex residual errors of calibrated two-port vector network analyzer

This article presents a new method for verification of the residual errors of calibrated two-port vector network analyzers based on a special time-domain technique. The method requires two devices under test including a high-precision air line. Calibration residual errors are extracted from a distance-frequency system model and special estimation algorithm based on the quasi-optimal unscented Kalman filter. Experimental studies were conducted in coaxial measurement environments and at the wafer level. Suitable applications of the proposed verification method are discussed.

RF Probe Technology: History and Selected Topics

Today, radio-frequency (RF) wafer probes play an important role in almost every step of the RF products lifecycle: from technology development, model parameter extraction, design verification, and debug to small-scale and final production test. By using RF probes, it became possible to measure true characteristics of the RF components at the wafer level. This halved research and development times and lowered the enormous costs of developing new products.

Calibration Standards Verification Procedure Using the Calibration Comparison Technique

This article examines the verification procedure of coplanar calibration standards based on the calibration comparison technique. For the first time, different commercially available alumina calibration substrates were compared using the NIST multiline TRL calibration procedure, calibration comparison approach, and the NIST GaAs CPW calibration reference material RM8130. The characteristic impedance of the verified calibration line standards is extracted using the multiline TRL procedure and the definition of the load standard resistance. The error circuit, describing difference of the substrate medium and the standard design is extracted. Finally, the worst case error bounds for the measurement of passive devices compared to the reference multiline TRL on the RM8130 are calculated for each tested substrate

Adaptive estimation of complex calibration residual errors of wafer-level S-parameters measurement system

This article presents a method for determining complex residual errors of calibrated two-port vector network analyzers. It utilizes the time-domain technique. Calibration residual errors are extracted from a distance-frequency system model using a special estimation algorithm based on the quasioptimal unscented Kalman filter. Because the method requires only three measurement conditions, it is in particular beneficial for on-wafer applications, as three test conditions can be obtained from using only one transmission line. Moreover, the length of the line can be relatively short. Experimental studies were performed and verified the proposed method.

State-of-the-art and future perspectives in calibration and de-embedding techniques for characterization of advanced SiGe HBTs featuring sub-THz f T /f MAX

This paper presents an overview of RF calibration and pad de-embedding techniques, discusses limitations and demonstrates methods for accuracy improvement applicable for the characterization of advanced BiCMOS HBTs. The impact of the reference plane location is discussed. Numerous experiments with different device geometries showed that the in-situ (on-wafer) calibration yields the most accurate results. For a probe-tip calibration, a multiple-dummy de-embedding is crucial to improve measurement accuracy. A comparison with the compact model (HICUM V2.30) confirmed the findings.

The influence of calibration substrate boundary conditions on CPW characteristics and calibration accuracy at mm-wave frequencies

This paper presents new experimental investigations of the influence of calibration substrate boundary conditions on CPW transmission line characteristics and calibration accuracy at millimeter wavelengths. A new configuration that decreases insertion loss of CPW transmission lines and improves calibration accuracy is suggested.