Fabrication, Characterization, and Physical Analysis of AlGaN/GaN HEMTs on Flexible Substrates

This paper reports on the dc analysis and radio frequency (RF) characterization of a flexible AlGaN/GaN high-electron mobility transistor with a 120-nm gate length. The device provides a maximum dc current density of 470 mA/mm and a peak extrinsic transconductance of 125 mS/mm under flat condition. When the substrate is bent with 0.88% strain, a rise in the 2-DEG density is experimentally observed through the diminution of the on-resistance. This phenomenon is physically attributed to the modification of the piezoelectric field within the barrier under tensile condition. The device also shows a current gain cutoff frequency (F_t) of 32 GHz and a power gain cutoff frequency (F_max) of 52 GHz. No major variations of RF performance are observed under bending.