Effect of Thermoelectric Leg Thickness in a Planar Thin Film TEC Device on Different Substrates

Abstract

Recently, mobile application processors (APs) have suffered from thermal issues such as local hot spot generation. Several approaches for chip cooling, such as dynamic thermal management, and heat pipe cooling, have been attempted so far, but, these solutions cannot completely eliminate increasing thermal issues. Therefore, in this study, we fabricated a planar type of thin film thermoelectric cooler (TEC) as an active cooling device for a mobile AP chip. We studied the effect of thickness on a planar thin film TEC device related to Joule heating and demonstrated the Peltier cooling effect on polyimide (PI) and Si substrates. The optimal thicknesses of n-type Bi2Te3 and p-type Sb2Te3 films were evaluated by ANSYS® simulation, and are 5.05 μm and 5.45 μm, respectively. It was shown that heat moves to the TE leg on the PI substrate, while the Si substrate serves as a heat sink according to the IR thermography analysis. The optimal thickness of the TE showed a temperature difference between the cold junction and hot junction up to 1.3 °C.