title: A Low-Leakage Epitaxial High-κ Gate Oxide for Germanium Metal-Oxide-Semiconductor Devices.
abstract: Germanium (Ge)-based metal-oxide-semiconductor field-effect transistors are a promising candidate for high performance, low power electronics at the 7 nm technology node and beyond. However, the availability of high quality gate oxide/Ge interfaces that provide low leakage current density and equivalent oxide thickness (EOT), robust scalability, and acceptable interface state density (D(it)) has emerged as one of the most challenging hurdles in the development of such devices. Here we demonstrate and present detailed electrical characterization of a high-κ epitaxial oxide gate stack based on crystalline SrHfO3 grown on Ge (001) by atomic layer deposition. Metal-oxide-Ge capacitor structures show extremely low gate leakage, small and scalable EOT, and good and reducible D(it). Detailed growth strategies and postgrowth annealing schemes are demonstrated to reduce Dit. The physical mechanisms behind these phenomena are studied and suggest approaches for further reduction of D(it).
authors: Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Chengqing
authors: C
authors: Hu
authors: Martin D
authors: MD
authors: McDaniel
authors: Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Aiting
authors: A
authors: Jiang
authors: Agham
authors: A
authors: Posadas
authors: Alexander A
authors: AA
authors: Demkov
authors: John G
authors: JG
authors: Ekerdt
authors: Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Edward T
authors: ET
authors: Yu
keywords: epitaxial oxides; germanium; high-κ dielectrics; interface traps; perovskites; semiconductor−oxide interfaces