Hybrid liquid-metal heat dissipation structure enabled by phase transition for flexible electronics

Abstract

Flexible electronics incorporating built-in thin-film semiconductors with soft substrates allow devices or systems to conform to desired shapes, creating opportunities for various novel applications. High radio-frequency (RF) power flexible devices play significant roles in flexible wireless communication and other miniaturized microwave systems in the future. However, high power operations of devices generate a massive amount of heat, and if not dissipated effectively, the excessive heat can degrade the performance of flexible active devices and even cause irreversible damage to the systems. In this work, we present a hybrid heat dissipation structure that can be used in flexible electronics where significant heat dissipation is needed. The structure was designed with finite element method-based simulations with the goal of achieving both high heat dissipation efficiency and mechanical flexibility. The structure was fabricated using a phase transition technique, greatly simplifying the fabrication process without need of handling liquid in the fabrication process, and was tested on an ultra-thin flexible AlGaN/GaN high electron mobility transistor (HEMT). The maximum power handled by the heat-managed HEMT measured from the I DS–V DS curve was 2.33 times larger than a reference HEMT without the heat dissipation structure. This demonstration opens new prospects for expanding the applications of flexible electronics toward high-power radio frequency regime in the future.