Microscopic four-point probe based on SU-8 cantilevers
A microscopic four-point probe (micro4PP) for resistivity measurements on thin films was designed and fabricated using the negative photoresist SU-8 as base material. The device consists of four microscopic cantilevers, each of them supporting a probe tip at the extremity. The high flexibility of SU-8 ensures a stable electrical point contact between samples and probe tip with all four electrodes even on rough surfaces. With the presented surface micromachining process, micro4PPs with a probe-to-probe spacing of 10–20 um were fabricated. Resistivity measurements on thin Au, Al, and Pt films were performed successfully. The measured sheet resistances differ by less than 5% from those obtained by a commercial macroscopic resistivity meter. Due to the low contact forces (Fcont<10−^4 N), the micro4PP is suitable to be applied also to fragile materials such as conducting polymers. Here the authors demonstrate the possibility of performing resistivity measurements on 100-nm-thick pentacene (C22H14) films with a sheet resistance Rs>10^6 ohm/?.
Record created on 2006-06-12, modified on 2016-08-08