Determination of the temperature coefficient of resistance from micro four-point probe measurements
Thomas A. Marangoni, Benny Guralnik, Kasper A. Borup, Ole Hansen, Dirch Hjorth Petersen
Abstract
Current characterization methods of the temperature coefficient of resistance (TCR) of thin films are often limited to slow macroscale measurements, which further require a direct determination of temperature. In this work, we present an innovative application of micro four-point probe (M4PP) sensing, which enables a fast, non-destructive, local measurement of Joule heating effects that can be translated into TCR of the thin film. Analytical expressions for the four-point resistance response to local heating, and ultimately the temperature profile during an M4PP measurement, are derived and validated against finite element models. The method is successfully demonstrated on three metal thin films (7, 10, and 16 nm platinum deposited on fused silica). We evaluate TCR using two different electrode configurations, resulting in unique temperature fields, and observe a measurement repeatability of <2% for each configuration. Furthermore, the M4PP-TCR method shows only a minor (∼18%) systematic offset relative to reference TCR measurements obtained via an independent physical property measurement system. Our results demonstrate a new technique for characterizing TCR on the micrometer scale, adequately backed by theory. The measurement time is just a few seconds and could allow for thin film TCR mapping or in-line process monitoring on test structures.