Reliable transfer technique of gold micro heater through different affinities of thiol ([sbnd]SH) and amine ([sbnd]NH2) groups

Abstract

This paper describes a modified dry peel-off process for the fabrication of gold micro heaters embedded in polydimethylsiloxane (PDMS), the characterization of the micro heaters, and the comparison of the measured results with simulated data. The modified dry peel-off process utilizes the difference in molecular adhesion between gold, amine (NH2), and thiol (SH). Three kinds of self-assembled monolayers (SAMs) were implemented in the process for controlling the adhesion between gold electrodes and crystalline silicon as well as between gold electrodes and PDMS. In this work, especially, the different affinities of 3-aminopropyl-triethoxysilane (APTES) and 3-mercaptopropyl-trimethoxysilane (MPTMS) to gold were exploited for the reliable transfer of three different shapes of gold micro heaters to new substrates. Octadecyltrichlorosilane (OTS) reduced the surface energy of silicon and enabled PDMS to easily detach from the silicon. Finally, a simple straight micro heater was characterized by using an infrared (IR) thermal microscopy, and its resistivity and temperature coefficient of resistance (TCR) were estimated to be 48nΩm and 0.0029K−1, respectively, from a temperature-resistance plot.