篇題：Fabrication and Characterization of Flexible AlGaN/GaN HEMTs on Kapton Tape
文章出處：IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 68, NO. 7, JULY, pp. 3320-3324, 2021
作者：許耕立與吳孟奇
任職單位及部門：清華大學電子工程研究所
In this work, we successfully used wet etching to remove Si substrate and transferred AlGaN/GaN HEMTs arrays with LG= 2 μm to the flexible Kapton tape. The area transferred of AlGaN/GaN epitaxial thin film reached to 1.2 x 1.2 cm2. The flexible HEMTs still exhibits excellent electrical properties with the Jds,max of 290 mA/mm, and the gm,max of 108 mS/mm. Furthermore, we analyzed physical mechanisms when devices under bending. Under bending, the tensile strain enhances the piezoelectric field within the AlGaN layer so that increase the 2DEG density. In the condition that flexible HEMTs are bent with radius of curvature = 0.3 cm, the Jds,max reaches to 346 mA/mm, and the gm,max achieves to 125 mS/mm. Besides, by pulse I-V measurement, we verified that the main reason for the decrease of DC characteristics is self-heating. As for the RF characteristics, we found that Si substrate removal can effectively decreases the output parasitic capacitances. Although the gm,max becomes half after transfer processes, the fT and the fmax of the flexible HEMTs still reach to 3.8 GHz and 6.5 GHz, respectively.
