AlN quasi-vertical Schottky barrier diode on AlN bulk substrate using Al0.9Ga0.1N current spreading layer

An aluminum nitride (AlN) quasi-vertical Schottky barrier diode (SBD) was fabricated on an AlN bulk substrate. An undoped AlN layer, a Si-doped Al0.9Ga0.1N current spreading layer and an AlN buffer layer were grown by plasma-enhanced molecular beam epitaxy. The epitaxial AlN layer was etched down to the n-Al0.9Ga0.1N layer to form an Ohmic contact. Ni/Au and V/Al/Ni/Au were deposited on the top AlN layer as Schottky contacts and on the exposed n-Al0.9Ga0.1N layer as Ohmic contacts, respectively. The Ohmic characteristics on the n-Al0.9Ga0.1N layer, capacitance-voltage (C-V) and current-voltage (I-V) characteristics of the AlN SBD were investigated.