MOCVD of Hafnium Silicate Films Obtained from a Single-Source Precusor on Silicon and Germanium for Gate-Dielectric Applications

Journal article


Publication Details

Author(s): Ryssel H, Jank M, Bauer A, Dirnecker T, Frey L
Journal: Chemical Vapor Deposition
Publisher: Wiley-VCH Verlag
Publication year: 2007
Volume: 13
Journal issue: 2-3
Pages range: 105-111
ISSN: 0948-1907


Abstract


In this work, hafnium silicate layers on Si and Ge wafers for gate dielectric application in metal-oxide-semiconductor devices are investigated. Films are deposited by metal-organic (MO)CVD using the single-source precursor Hf(acac)2(OSitBuMe2)2. This precursor exhibits good properties in terms of hydrolysis stability, volatility, and deposition. However, precursor decomposition is affected by surface conditions. Films deposited on Si wafers reveal high C contamination (up to 20 at %) and low Si content (up to 20 at%). In contrast, for film deposition on Ge wafers, no C contamination can be detected and Si incorporation is delayed until after about 15 nm HfO2 dielectric growth. Post-deposition rapid thermal annealing in an O2 atmosphere causes crystallization of deposited films, Si and Ge redistribution in the dielectric, respectively, and interfacial layer growth. However, oxygen annealing was also found to reduce effective oxide thickness (EOT) significantly compared to as-deposited films, which is attributed to crystallization effects. However, scaling of EOT is limited by that interfacial layer growth. Leakage currents are mainly caused by trap-related conduction mechanisms. Energy levels of involved traps decrease with increasing crystallization and/or Hf content, and values of 0.5 eV and 1 eV related to Hf and Si bonds, respectively, are obtained. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.



FAU Authors / FAU Editors

Dirnecker, Tobias Dr.
Lehrstuhl für Elektronische Bauelemente
Frey, Lothar Prof. Dr.
Lehrstuhl für Elektronische Bauelemente
Jank, Michael Dr.
Lehrstuhl für Elektronische Bauelemente

Last updated on 2018-09-08 at 13:38