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 10/sup 14/-10/sup 16/ cm/sup -3/. Values for unintentionally and intentionally doped n-type films range from 10/sup 17/ to 10/sup 20/ cm/sup -3/, and for intentionally doped (Mg) p-type from 10/sup 15/ to 10/sup 17/ cm/sup -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 10/sup 3/ 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 10/sup 3/ Ohm. Both PAPVD and sputtered unintentionally doped n-type ScN show rectifying behavior with p-Si. The leakage current is less than 10/sup -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/sup -5/ A.