Direct Measurement of Thermal Boundary Resistance Reduction Due to Electron Carriers by Photothermal Radiometery

Abstract

Abstract A thermal boundary resistance occurs between any two surfaces that are not in perfect contact with each other. It is well predicted that this thermal resistance decreases as heat carriers, typically phonons or electrons, cross the contact surface. While phonon transport and electron transport are well documented in a number of conditions, direct measurement of the electron contribution to thermal boundary resistance across micro layers has not been shown. Understanding the effect of electrons on the heat transfer of thin layer is very important in understanding the thermal behavior of micro- and nano-electronics, which has impact on both the life and the reliability of electronics. This paper presents an experimental test on the heat transfer as electrons cross the boundary of an n-doped Schottky Diode. Photothermal Radiometry (PTR) measurements were then taken to determine the thermal boundary resistance. Measurements were made on the same diode in both the open and closed state. The obtained open and closed fit parameters were then compared with each other to determine the reduction in thermal boundary resistance. It was found that the thermal boundary resistance of the diode in its opened state was 8.4 K m /GW; while the thermal boundary resistance was 6.4 K m /GW when the Schottky diode was closed with current of 100 mA. This represents a reduction in the thermal boundary resistance of approximately 24% for the case where the electrons were crossing the boundary. This result confirms experimentally that the electron heat transport effectively reduces the thermal resistance across boundaries.