17.4 Micromachined p-GaN Gate Normally-off PowerHEMT with an Optimized Air-Bridge Matrix Layout Design

In this work, a micromachined P-GaN power high electron mobility transistor (HEMT) on Si substrate with new air-bridged matrix design was demonstrated. After removal of the Si substrate beneath the P-GaN HEMT, a significant breakdown voltage improvement was observed. The drain and source terminals were arranged as the matrix type and the 3 m-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 improved.