A Novel Micromachined AlGaN/GaN Power HEMT With Air-Bridged Matrix Heat Redistribution Layer Design

This letter develops a thermally stable micromachined AlGaN/GaN high electron mobility transistor (HEMT) on an Si substrate with an air-bridged heat redistribution layer design. After removal of the Si substrate beneath the HEMT, a significant breakdown voltage improvement was observed. The drain and source terminals were arranged as the matrix type. The 3 μm-thick Au was adopted for terminals connection and current redistribution layer of the proposed power cell. Compared with the traditional multi-fingers layout, the current density was doubled. In addition, the self-heating phenomenon of power cell was also suppressed by the removal of the substrate and air-bridged matrix layouts.