Development of on-wafer calibration methods and planar Schottky diode characterisation at THz frequencies

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto. fi Author Krista Dahlberg Name of the doctoral dissertation Development of on-wafer calibration methods and planar Schottky diode characterisation at THz frequencies Publisher School of Electrical Engineering Unit Department of Radio Science and Engineering Series Aalto University publication series DOCTORAL DISSERTATIONS 128/2014 Field of research Radio Engineering Manuscript submitted 9 May 2014 Date of the defence 24 September 2014 Permission to publish granted (date) 25 August 2014 Language English Monograph Article dissertation (summary + original articles) Abstract This thesis focuses on development of on-wafer calibration methods for S-parameter measurements and Schottky diode characterisation at millimeter wave and terahertz frequencies. The radio frequency characteristics of components at the wafer level are obtained using on-wafer S-parameter measurements with a vector network analyzer. In general an error network including eight error terms is used to calibrate the on-wafer S-parameter measurements, but in measurement configurations affected by leakage the use of full 16-term error network can be profitable. In this thesis a novel 16-term calibration method based on reciprocity conditions of the error network is introduced and demonstrated with simulations and practical on-wafer measurements. The developed calibration method enables the calibration of the full 16-term error network using only four calibration standards. The method is limited to second-tier calibration of reciprocal error networks with a pre-calibrated network analyzer, when the reciprocity assumption is valid. Also a novel method to determine Line-Reflect-Reflect-Match (LRRM) calibration standards for reciprocal 16-term error network is presented. The Line standard and the resistance of the Match standard need to be exactly known and the reactances of the two unknown lossless reflect standards (typically Short and Open) and the Match standard are solved using the raw S-parameter data of the calibration standard measurements. The accuracy of the known S-parameters or self-calibration results of the calibration standards can be verified as a by-product of the 16-term reciprocal calibration. LRRM is only one possible combination of the four calibration standards to solve the reciprocal 16-term error network. In this thesis all possible non-singular combinations are solved with a simulation approach. Schottky diodes are significant components in the millimeter wave and terahertz frequency applications. Traditionally Schottky diodes are characterised by current-voltage, capacitancevoltage, and S-parameter measurements. The design of the millimeter wave and terahertz diode mixers relies heavily on the extracted parameters from the traditional characterisation measurements. However, the diode operation in the final application such as a mixer cannot be completely predicted by using the extracted parameters. In this thesis a novel mixer-based characterisation method of discrete planar Schottky diodes is presented. A fundamental mixer test jig for single-anode Schottky diodes and a subharmonic mixer test jig for antiparallel Schottky diodes are developed to characterize and compare the mixer operation of different diodes at 183 GHz.This thesis focuses on development of on-wafer calibration methods for S-parameter measurements and Schottky diode characterisation at millimeter wave and terahertz frequencies. The radio frequency characteristics of components at the wafer level are obtained using on-wafer S-parameter measurements with a vector network analyzer. In general an error network including eight error terms is used to calibrate the on-wafer S-parameter measurements, but in measurement configurations affected by leakage the use of full 16-term error network can be profitable. In this thesis a novel 16-term calibration method based on reciprocity conditions of the error network is introduced and demonstrated with simulations and practical on-wafer measurements. The developed calibration method enables the calibration of the full 16-term error network using only four calibration standards. The method is limited to second-tier calibration of reciprocal error networks with a pre-calibrated network analyzer, when the reciprocity assumption is valid. Also a novel method to determine Line-Reflect-Reflect-Match (LRRM) calibration standards for reciprocal 16-term error network is presented. The Line standard and the resistance of the Match standard need to be exactly known and the reactances of the two unknown lossless reflect standards (typically Short and Open) and the Match standard are solved using the raw S-parameter data of the calibration standard measurements. The accuracy of the known S-parameters or self-calibration results of the calibration standards can be verified as a by-product of the 16-term reciprocal calibration. LRRM is only one possible combination of the four calibration standards to solve the reciprocal 16-term error network. In this thesis all possible non-singular combinations are solved with a simulation approach. Schottky diodes are significant components in the millimeter wave and terahertz frequency applications. Traditionally Schottky diodes are characterised by current-voltage, capacitancevoltage, and S-parameter measurements. The design of the millimeter wave and terahertz diode mixers relies heavily on the extracted parameters from the traditional characterisation measurements. However, the diode operation in the final application such as a mixer cannot be completely predicted by using the extracted parameters. In this thesis a novel mixer-based characterisation method of discrete planar Schottky diodes is presented. A fundamental mixer test jig for single-anode Schottky diodes and a subharmonic mixer test jig for antiparallel Schottky diodes are developed to characterize and compare the mixer operation of different diodes at 183 GHz.