Mechanism of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures via laser annealing Projects supported by the National Natural Science Foundation of China (Grant Nos. 51577169 and 51777187) and the National Key Research and Development Program of China (Grant No. 2017YFB0402804). |
The AFM and optical microscope images of the surface morphology for the ohmic structure (a) without annealing, (b) after RTA at 860 °C for 30 s in N2 ambient, and (c) after LA at a laser energy density of 2.99 J/cm2. RMS in the figure stands for root mean square. |