Generalized four-point characterization method using capacitive and ohmic contacts

Kim, B. S., Zhou, W., Shah, Y. D. , Zhou, C., Işık, N. and Grayson, M. (2012) Generalized four-point characterization method using capacitive and ohmic contacts. Review of Scientific Instruments, 83(2), 024703. (doi: 10.1063/1.3677331) (PMID:22380109)

Abstract

In this paper, a four-point characterization method is developed for samples that have either capacitive or ohmic contacts. When capacitive contacts are used, capacitive current- and voltage-dividers result in a capacitive scaling factor not present in four-point measurements with only ohmic contacts. From a circuit equivalent of the complete measurement system, one can determine both the measurement frequency band and capacitive scaling factor for various four-point characterization configurations. This technique is first demonstrated with a discrete element four-point test device and then with a capacitively and ohmically contacted Hall bar sample over a wide frequency range (1 Hz–100 kHz) using lock-in measurement techniques. In all the cases, data fit well to a circuit simulation of the entire measurement system, and best results are achieved with large area capacitive contacts and a high input-impedance preamplifier stage. An undesirable asymmetry offset in the measurement signal is described which can arise due to asymmetric voltage contacts.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Shah, Dr Yash Diptesh
• Authors: Kim, B. S., Zhou, W., Shah, Y. D., Zhou, C., Işık, N., and Grayson, M.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Review of Scientific Instruments
• Publisher: American Institute of Physics
• ISSN: 0034-6748
• ISSN (Online): 1089-7623
• Published Online: 02 February 2012
• Copyright Holders: Copyright © 2012 American Institute of Physics
• First Published: First published in Review of Scientific Instruments 83:024703
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher