First-principles simulations of the leakage current in metal-oxide-semiconductor structures caused by oxygen vacancies in HfO2 high-K gate dielectric

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2008-01, Vol.205 (1), p.199-203
• Main Authors: Mao, L. F., Wang, Z. O.
• Format: Article
• Language: English
• Subjects: 73.40.Gk; 77.55.+f; 77.84.Bw; 85.30.De; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Exact sciences and technology; Metal-insulator-semiconductor structures (including semiconductor-to-insulator); Physics
• ISSN: 1862-6300; 0031-8965; 1862-6319
• DOI: 10.1002/pssa.200723166

HfO2 high‐K gate dielectric has been used as a new gate dielectric in metal–oxide–semiconductor structures. First‐principles simulations are used to study the effects of oxygen vacancies on the tunneling current through the oxide. A level which is nearly 1.25 eV from the bottom of the conduction band is introduced into the bandgap due to the oxygen vacancies. The tunneling current calculations show that the tunneling currents through the gate oxide with different defect density possess the typical characteristic of stress‐induced leakage current. Further analysis shows that the location of oxygen vacancies will have a marked effect on the tunneling current. The largest increase in the tunneling current caused by oxygen vacancies comes about at the middle oxide field when defects are located at the middle of the oxide. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)