AlGaN/GaN MIS-HEMT With AlN Interface Protection Layer and Trench Termination Structure

Abstract

In this brief, an AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistor (MIS-HEMT) with pulsed laser deposited AlN interface protection layer (IPL) and trench termination ( ${T}^{\textsf {2}}$ ) structure is experimentally and theoretically investigated. The AlN IPL could effectively improve the interface quality and reduce the interface trap density, which is verified by frequency-dependent ${C}$ – ${V}$ measurement and conductance method. The ${T}^{\textsf {2}}$ structure extends the depletion region and increases the average electric field (E-field) strength between the gate and drain, achieving an enhanced breakdown voltage (BV). The measured BV and saturated output current density are 412 V and 505 mA/mm for the device at ${L}_{\textsf {G}}/{L}_{\textsf {GS}}/{L}_{\textsf {GD}}/{W}_{\textsf {G}}= \textsf {1.5}$ /1.5/5/ $10~\mu \text{m}$ , respectively. Compared with the MIS-HEMT without ${T}^{\textsf {2}}$ structure, the proposed device increases the BV by 63%.