Dynamic piezotronic effect modulated AlGaN/GaN HEMTs with HfZrOx gate dielectric

Abstract

High electron mobility transistors (HEMTs) based on AlGaN/GaN heterojunctions show promising applications in high-performance power electronics. Having to face the limited device performance caused by electrically unstable issues, high-κ gate dielectric has been brought into HEMTs (forming MOS-HEMTs) to make a breakthrough. Impressively, a high-κ HfZrOx (HZO) dielectric has been proved to enable the HEMTs to exhibit enhanced performances, e.g., higher output performance, lower leakage current, and better surface properties. Additionally, by coupling piezoelectric and semiconductor properties, piezotronic effect also provides a novel approach for optimizing HEMTs with the use of external stress. Here, we present dynamic piezotronic effect of AlGaN/GaN HEMTs with HZO gate dielectric in pulse voltage modes. When the GaN layer is suffered from tensile stress, the DC and pulse output characteristics of the MOS-HEMTs show significantly decreased trends, and the gate leakage current shows a slight increase. Moreover, theoretical analysis based on Crosslight simulation and a self-consistent model shows that the applied tensile stress can effectively improve the energy band height of triangular potential well and affect the energy states of defects. This work not only provides an inspiration for the modulated device performance in dynamic piezotronic effect, but also expands the application prospect of HEMTs in a strain-controlled platform.