Characterization of ScN heterojunctions

ScN metal contacts and unintentionally doped n-type ScN with p type Si, and isotype (n-n) ScN and GaN junctions are fabricated and tested. ScN films grown by plasma assisted physical vapor deposition (PAPVD) and RF-sputtering show the carrier concentration for intrinsic ScN to be between 10¹⁴-10¹⁶ cm^-3. Values for unintentionally and intentionally doped n-type films range from 10¹⁷ to 10²⁰ cm^-3, and for intentionally doped (Mg) p-type from 10¹⁵ to 10¹⁷ cm^-3. Metal contacts (Pd, Ni, Ti) are dc-sputtered on the ScN films. For the n-type PAPVD ScN, the best ohmic contact is Ti, with the contact resistance in the range 10³ Ohm; Pd and Ni contacts are similar to Ti. For the n-type sputtered films, the best ohmic contact is Pd with resistance in the tens of Ohms range. Ti forms ohmic contacts with slightly higher resistance than Pd. Ni contacts have resistance in the range 10³ Ohm. Both PAPVD and sputtered unintentionally doped n-type ScN show rectifying behavior with p-Si. The leakage current is less than 10^-5 A at -4 V when temperature is 260-300 K. The leakage current is found to slightly increase at 340 K while the forward current drops. The turn-on voltage for this junction is found to be in the range 1.12-1.45 V. ScN/GaN isotype (n-n) heterojunctions display rectifying behavior with turn on voltages between 0.57 V and 1.25 V and leakage current at -4 V in the range of 10 ^-5 A