Bias-Dependence of Electroluminescence in AlGaN/GaN High-Electron-Mobility Transistors on SiC Substrate

Abstract

This paper investigates bias-dependence of electroluminescence (EL) in an AlGaN/GaN HEMT fabricated on a SiC substrate. The HEMT exhibited a low-intensity reddish EL at the gate electrode at a drain voltage (Vds) of 30 V, which was confirmed with combination of a top-side view using a CMOS sensor camera and a back-side view using a silicon-intensified CCD. As Vds was increased to 48 V, color change from low-intensity red to high-intensity white was accompanied with shift of the location from the gate to the drain edge. The changes in the EL are attributed to a shift of the high electric field from the gate to the drain electrode and a concentration of electric field near the drain edge.

Evaluation of electroluminescence of AlGaN/GaN HEMT on free-standing GaN substrate

“…14,17,20) Recently, our group found that a severe current collapse occurs at the same time of a shift of the EL from the gate electrode to the drain electrode of HEMTs on a SiC substrate (GaN-on-SiC) under an increased drain voltage (V ds ). 18,24) However, to our best knowledge, few reports studied the role of the substrate on the EL in HEMTs with a correlation to current collapse.…”

“…We observed EL location from the backside of HEMTs through GaN and SiC substrates using an emission microscope, Hamamatsu Photonics PHEMOS-1000. 18,24) This microscope has a silicon-intensified CCD (Si-CCD) camera with a detectable wavelength range of 300-1100 nm and a spatial resolution of sub-micron.…”