Figure 7
Spectral analysis. The EDS spectra analysis for (a) sample 1: Ti/Al/Ti/Au; (b) sample 2: Ti/Al/Ni/Au; (c) sample 3: Ti/Al/Ta/Au; and (d) sample 4: the optimized Ti/Al/Ta/Au after annealing at 850°C for 30 s (the FIB image of the cross-sectional ohmic contact with the EDS spectra measuring point is shown in the upper left of (a), and the distance from the AlGaN/GaN layers to the alloyed ohmic contact surface is 80 nm, which is fixed to all of the measured samples).