Low contact resistance to digital alloys of n-type AlGaN/AlN with high average Al concentration is described. Low-energy electron diffraction was used to evaluate surface precleaning with HCl and buffered HF. The contact metallization consisting of a stack of Ti/Al/Ti/Au, 20/100/45/60 nm in thickness, was e-beam deposited and etch-patterned. The lowest specific contact resistance of 5.6 × 10-5 Ω · cm2 was obtained after annealing in N2 ambient at 700 °C.
- Light-emitting diode
- Ohmic contact