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

In this brief, an AlGaN/GaN metal-insulator- semiconductor high-electron-mobility transistor (MISHEMT) with pulsed laser deposited AlN interface protection layer (IPL) and trench termination (T
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
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
_G
/L
_GS
/L
_GD
/W
_G
= 1.5/1.5/5/10 μm, respectively. Compared with the MIS-HEMT without T
²
structure, the proposed device increases the BV by 63%.