Local temperature evaluation of Si ribbon under a temperature gradient by Kelvin-probe force microscopy
摘要
Although Kelvin-probe force microscopy (KPFM) is a powerful tool for evaluating the thermoelectromotive force and Seebeck coefficient on a micro/nanometer scale, it is essential to directly determine the local temperature difference. We developed a measurement method for the local temperature difference by KPFM. The local temperature of Si and Si-on-insulator (SOI) wafers were evaluated through the Fermi-energy shift originating from a temperature change, and they were found to have a linear relation to the reference temperature measured by a thermocouple (TC). However, the KPFM-determined temperature was overestimated because of the influence of charges trapped at the Si and native oxide (SiO2) interface. Therefore, it can be concluded that the local temperature can be measured by KPFM after the temperature is calibrated by a TC on the target material. It was also demonstrated that the local temperature difference was evaluated to be 1.67 K for two Si ribbons with an 8.6 µm distance when a temperature gradient was applied.