Band alignments of sputtered dielectrics on GaN

• Published in: Journal of physics. D, Applied physics Vol. 53; no. 7; pp. 75303 - 75312
• Main Authors: Supardan, S N, Das, P, Major, J D, Hannah, A, Zaidi, Z H, Mahapatra, R, Lee, K B, Valizadeh, R, Houston, P A, Hall, S, Dhanak, V R, Mitrovic, I Z
• Format: Journal Article
• Language: English
• Published: IOP Publishing 13.02.2020
• Subjects: band offsets; dielectrics; gallium nitride; high; Kraut's method; metal-insulator-semiconductor capacitor; x-ray photoelectron spectroscopy
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/1361-6463/ab5995

The band alignments of sputtered ZrO2, Al2O3 and MgO on GaN have been measured experimentally using x-ray photoelectron spectroscopy (XPS). The valence band offsets (±0.2 eV) for ZrO2, Al2O3 and MgO on GaN using Kraut's method and charge-corrected XPS core levels were found to be 0.4 eV, 1.1 eV and 1.2 eV with corresponding conduction band offsets (±0.2 eV) of 1.3 eV, 2.0 eV and 2.8 eV, respectively. The electrical characterization of metal insulator semiconductor (MIS)-capacitors with different gate dielectrics (ZrO2, Al2O3 and MgO) has been performed as well. The current density of the MIS-capacitors with gate dielectrics MgO and Al2O3 at a positive bias of 1 V show lower leakage currents of 3.2  ×  10−6 A cm−2 and 5.3  ×  10−6 A cm−2 respectively, whereas, the MIS-capacitors with ZrO2 gate dielectric have the highest leakage current of 6.2  ×  10−4 A cm−2 at 1 V.