Demonstration of compensated n-type scandium nitride Schottky diodes

Abstract

Scandium nitride is an emerging group III-B transition metal pnictide and has been studied extensively for its thermoelectric properties, as interlayers for defect-free GaN growth, in epitaxial metal/semiconductor superlattices, and recently for its polaritonic and optoelectronic synaptic functionalities. However, to realize the full potential of its semiconducting properties in electronic, thermionic, and optoelectronic device applications, it is necessary to develop Schottky diodes of ScN that are missing thus far. Here we show Schottky diodes of ScN with elemental metals such as silver (Ag) and gold (Au). As-deposited ScN thin films exhibit a high electron concentration in the (1-4) × 1020 cm-3 range due to unintentional oxygen doping. These excess electrons are compensated by Mg hole doping, leading to a wider depletion region at the metal/ScN interface for activated electronic transport. Current-voltage (I-V) characteristics show the rectification nature in ScN/Ag and ScN/Au diodes, and the barrier heights of 0.55± 0.05 eV and 0.53± 0.06 eV, respectively, are obtained. Interface annealing with time and temperature results in a slight increase in the forward junction potential. The capacitance-voltage (C-V) measurements also revealed the presence of interface trap states. The demonstration of Schottky diodes marks an important step in realizing the full potential of ScN in electronic, thermionic, and optoelectronic devices.

Reversal of Band-Ordering Leads to High Hole Mobility in Strained p-type Scandium Nitride

“…25 Schottky diodes of ScN with elemental metals such as Au and Ag have been experimentally demonstrated recently. 26 Traditionally, molecular beam epitaxy or magnetron sputterdeposited ScN thin films exhibit a high n-type carrier concentration in the (2−5) × 10 20 cm −3 range and electron mobility of 90−130 cm 2 /(V s) at room temperature. 27 However, utilizing the hybrid vapor phase epitaxy (HVPE), the highest electron mobility of 284 cm 2 /(V s) has been achieved in micron-sized thick ScN films at room temperature.…”

“…Theoretical calculations have also predicted that ScN would be an excellent barrier layer in magnetic tunnel junctions . Schottky diodes of ScN with elemental metals such as Au and Ag have been experimentally demonstrated recently …”