Investigation of Electric Field Profile and associated parameters with Embedded Metal Layer in Field Plate AlGaN/GaN HEMTs

Abstract

Electric field initiates various failure mechanism in an III-N based AlGaN/GaN HEMTs. The material properties of the GaN-HEMTs under the influence of electric field activates physical mechanisms like converse piezoelectric effect (CPE), crack/defect migration, trapping, which deteriorate the electrical behaviour of the device leading to permanent failure. The drain side of the gate edge has the highest electric field and is the hub of all the reliability concerns in a GaN HEMT, which is mitigated with field plate (FP) technology. However, the FP edge is now subjected to these degradation phenomena. The present work aims at suppressing the strong electric fields at the FP gate edge using an embedded metal layer that shields the electric field from reaching the gate edge. Calibrated numerical simulations have been carried out on the proposed device structure to observe the viability in consideration. It is found that the electric field at the FP edge reduces by around 3%. Also, CPE and electron temperature reduce by 20%, and 14%, respectively. Since the proposed device structure can considerably mitigate the electric field, CPE, and electron temperature, it is expected that it will pave a path for improved and reliable devices in the future.