Precise Measurements of Active Devices

Abstract

Active devices such as transistors and amplifiers play a vital role in today’s ever-growing semiconductor industry which makes active device characterization an important step in the design process. This thesis assignment is dedicated to investigate methods for the characterization of active devices operating under non-50 Ω conditions. The systems currently used for characterization of active devices are called load-pull systems [1]. The investigation scope includes system-level topology, S-parameter calibration and power calibration in active load pull systems. Additionally, linearity analysis and behavourial modelling of a IQ modulator is also conducted as it is a core component used in active load-pull systems to synthesize various reflection coefficients. Furthermore, a meterlogy grade impedance standard substrate (ISS) is also presented to investigate noise and linearity behaviour of VNA upto 330 GHz. The design con sists of SOLR (Short-Open-Load-Reciprocal) [2] calibration structures up to 67 GHz and TRL (Thru-Reflect-Line) [3] calibration structures up to 330 GHz. In addition to calibration and validation structures, the ISS also consists structures for 16 term error calibration which will be used for full two port calibration and probe cross-talk inves tigation. Finally, structures for DC 4-point measurement (Van der pauw method [4]) are also designed for material characterization. Finally, the calibration substrate layout is presented which allows user to perform manual as well as automated probing. The reference substrate is fabricated by IMS CHIPS, Institut für Mikroelektronik Stuttgart.