Improving Thermal Effects and Reduction of Self-heating Phenomenon in AlGaN/GaN/Si Based HEMT

Abstract

In this paper, we reduce the self-heating effects of high-electron-mobility transistors (HEMT) by using changes in material and structure. In the first step, the 6H-SiC layer is used both as a substrate layer and as a passive layer. The thermal conductivity of SiC materials is very high, which reduces the heat under the gate. In the second step, the barrier layer is used by a combination of AlGaN and InGaN as a heterojunction. InGaN material is used at the point where the hot spot occurs. These changes in the barrier layer cause the heat to be uniformly distributed under the gate, so that the combination and recombination of electrons and holes in the hot spot are reduced. In the next step, the heat generated in the structure is directed to outside of the structure by a metal plate or field plate. In this paper, the selected structure for reference is fabricated in recent years. Different layers of materials have been grown on the Si substrate layer (AlGaN/GaN/Si). After the changes, the output current increased by 25%, and overall the heat generated in the structure decreased by 40%. The proposed structure is suitable for high-power and high-frequency circuits.