Realization of homojunction PN AlN diodes

Abstract

Aluminum nitride (AlN) is an insulator that has shown little promise to be converted to a semiconductor via impurity doping. Some of the historic challenges for successfully doping AlN include a reconfigurable defect formation known as a DX center and subsequent compensation that causes an increase in dopant activation energy resulting in very few carriers of electricity, electrons, or holes, rendering doping inefficient. Using crystal synthesis methods that generate less compensating impurities and less lattice expansion, thus impeding the reconfiguration of dopants, and using new dopants, we demonstrate: (a) well behaved bulk semiconducting functionality in AlN, the largest direct bandgap semiconductor known with (b) substantial bulk p-type conduction (holes = 3.1 × 1018 cm−3, as recently reported in our prior work), (c) dramatic improvement in n-type bulk conduction (electrons = 6 × 1018 cm−3, nearly 6000 times the prior state-of-the-art), and (d) a PN AlN diode with a nearly ideal turn-on voltage of ∼6 V for a 6.1 eV bandgap semiconductor. A wide variety of AlN-based applications are enabled that will impact deep ultraviolet light-based viral and bacterial sterilization, polymer curing, lithography, laser machining, high-temperature, high-voltage, and high-power electronics.