Electrical Degradation of <i>In Situ</i> SiN/AlGaN/GaN MIS-HEMTs Caused by Dehydrogenation and Trap Effect Under Hot Carrier Stress

Abstract

The gate and drain bias dependence of hot electron-induced degradation in GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) was investigated in this work. Devices exhibit an abnormal increase in peak transconductance ( G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ,max) during hot carrier stress (HCS) and a partially quick recovery of that after removing the electrical stress. A physical model is proposed to explain the abnormal electrical characteristics caused by HCS. By using density functional theory (DFT), we calculated the energy for electrons to dehydrogenate preexisting [N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ga</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ] <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> complexes in GaN layer during stress. The dehydrogenation of defects affects the G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m,max</sub> of devices. Meanwhile, the neutralization of donor traps in AlGaN barrier layer also plays a significant role in the increase of G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m,max</sub> and the detrapping effect of electrons from these traps after removing the electrical stress accounts for the partially quick recovery of G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m, max</sub> .