Understanding the Impact of Annealing on Interface and Border Traps in the Cr/HfO2/Al2O3/MoS2 System

• DOI: 10.1021/acsaelm.8b00103
• Publication Date: 2019-06-25T13:32:57Z
• Authors: Peng Zhao; Andrea Padovani; Pavel Bolshakov; Ava Khosravi; Luca Larcher; Paul K. Hurley; Christopher L. Hi...; Robert M. Wallace; Chadwin D. Young
• Keywords: Forming gas

Top-gated, few-layer MoS2 transistors with HfO2 (6 nm)/Al2O3 (3 nm) gate dielectric stacks are fabricated and electrically characterized by capacitance–voltage (C–V) measurements to study active traps (Dit) in the vicinity of Al2O3/MoS2 interface. Devices low Dit high both observed C–V characterization, impact H2/N2 forming gas annealing at 300 400 °C on density distribution is studied. A anneal able reduce significantly, while increases defects stack. Simulation modeled suggests a sizable decrease Dit, half amount positive fixed charge dielectric, slightly increased unintentional doping after anneal. In as-fabricated devices displaying levels, energy located interface continuous from conduction band edge down 0.13–0.35 eV below edge. plausible origin our experiments could come unexpected oxygen atoms that fill sulfur vacancies during UV–O3 functionalization treatment. The border trap concentration Al2O3 same, before anneal, suggesting different traps, possibly due low-temperature atomic-layer-deposited process.