Generalized four-point characterization method using capacitive and ohmic contacts |
| |
Authors: | Kim Brian S Zhou Wang Shah Yash D Zhou Chuanle Işık N Grayson M |
| |
Affiliation: | Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, USA. |
| |
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. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|