Mg-implanted bevel edge termination structure for GaN power device applications

Herein, we propose and demonstrate the edge termination for GaN-based one-sided abrupt p-n junctions. The structure is comprised of a combination of a shallow negative bevel mesa and selective-area p-type doping under the mesa. Based on the Technology Computer Aided Design (TCAD) simulation, the maximum electric field at the junction edge is markedly reduced to approximately 1.3 times that of the parallel-plane electric field in the proposed structure, which is almost half of the unimplanted diode. The TCAD simulation also shows that the shallow mesa angle of 6 degrees effectively reduces the optimum acceptor concentration (N-a) in the implanted region and enhances the breakdown voltage. The optimum N-a value can be covered by the proposed technology based on the Mg-ion implantation and subsequent ultra-high-pressure annealing (UHPA). Using the formation of the shallow bevel mesa, the Mg-ion implantation, and the UHPA process, we experimentally demonstrate the p-n diodes with a breakdown voltage over 600V, which is in good agreement with the TCAD simulation. The proposed method can be applied to a vertical trench-gate metal-oxide-semiconductor field-effect transistor with a high figure-of-merit.

Automated summary

The proposed method demonstrates an edge termination technique for GaN-based one-sided abrupt p-n junctions, utilizing a combination of shallow negative bevel mesa and selective-area p-type doping. Through TCAD simulation and experimental verification, the approach significantly reduces the maximum electric field at the junction edge and enhances the breakdown voltage of the p-n diode.