Enhanced electrical properties of Nb-doped a-HfO2 dielectric films for MIM capacitors

• Published in: AIP advances Vol. 10; no. 11; pp. 115117 - 115117-6
• Main Authors: Bon, Chris Yeajoon, Kim, Dami, Lee, Kanghyuk, Choi, Sungjoon, Park, Insung, Yoo, Sang-Im
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.11.2020; AIP Publishing LLC
• Subjects: Aluminum; Capacitors; Dielectric properties; Electrical properties; Hafnium oxide; Leakage current; Magnetron sputtering; Niobium; Room temperature; Silicon wafers; Thin films; X ray photoelectron spectroscopy
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/5.0024783

We report enhanced electrical properties of metal–insulator–metal (MIM) capacitors consisting of Al (100 nm)/Nb-doped a-HfO2 (∼30 nm)/Pt (100 nm) on a p-type silicon wafer, where Nb-doped amorphous HfO2 (a-HfO2) layers were deposited by radio frequency magnetron sputtering in various low oxygen partial pressures at room temperature. Polycrystalline HfO2 targets with three different Nb contents of 0 mol. %, 6 mol. %, and 10 mol. % were used in this study. Compared with the leakage current of the undoped a-HfO2 film (∼1.1 × 10−8 A cm−2 at 1 V), greatly reduced leakage currents (∼3.7 × 10−10 A cm−2 at 1 V) with no significant alteration in the dielectric constants (∼22) were obtainable from the MIM samples composed of Nb-doped a-HfO2 films, which is attributable to the suppression of oxygen vacancy formation based on the XPS analysis results. The Nb-doped a-HfO2 dielectric thin films also exhibited improved voltage nonlinearity compared to undoped HfO2. These results indicate that Nb-doped a-HfO2 has potential application as a high-κ dielectric material in MIM capacitors.