Accurate determination of the peak channel temperature by an electrical method combined with EL mapping technique in In0.17Al0.83N/GaN HEMTs

In this work, an effective electrical method combined with EL mapping technique is developed to evaluate the peak channel temperature (T-p) in lattice-matched InAlN/GaN high electron mobility transistors. Electroluminescence (EL) is observed when devices operate at different dissipated power with V-g = 0 V. EL intensity shows a triangular distribution along the channel and the highest intensity is near the gate edge towards the drain. Assuming a linear relationship between the EL intensity and the channel temperature, a simple triangular resistivity distribution is established. The relevant temperature coefficient is directly obtained by measuring the channel resistance as a function of the temperature. Due to the different physical nature, the resultant T-p values are obviously higher than the average channel temperature derived by the traditional electrical measurements, and are very close to the peak values determined by the Raman spectroscopy. Therefore, our proposed method is more suitable for practical large-scale production.