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SiON as a barrier layer for depositing an Al 2 O 3 thin film on Si for gate applications
Author(s) -
Zhen Congmian,
He Gang,
Wang Xiaoliang,
Shimogaki Yukihiro
Publication year - 2009
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3124
Subject(s) - x ray photoelectron spectroscopy , analytical chemistry (journal) , wafer , dielectric , chemical vapor deposition , annealing (glass) , oxide , layer (electronics) , refractive index , gate dielectric , materials science , high κ dielectric , equivalent oxide thickness , chemistry , gate oxide , optoelectronics , nanotechnology , voltage , chemical engineering , composite material , electrical engineering , metallurgy , chromatography , transistor , engineering
Oxynitridization of an Si wafer was conducted by rapid thermal annealing in NH 3 and O 2 . The refractive index of the SiON barrier layer formed at 1000 °C for 0.5 min was relatively high, about 1.96 at 589 nm, showing that the oxynitridized layer formed was compact. An Al 2 O 3 film was then deposited on the SiON layer by metalorganic chemical vapor deposition using new chemical vapor deposition chemistry. X‐ray photoelectron spectroscopy showed that the SiON barrier layer effectively prevents the formation of a layer of SiO 2 or aluminum silicate at the interface between the Al 2 O 3 layer and the Si wafer. Electrical measurements confirmed that few mobile charges were found to exist in the Al 2 O 3 film. The higher Al 2 O 3 dielectric constant and the lower equivalent oxide thickness were achieved when the sample was subjected to oxynitridization. A reduced flat band voltage shows that the SiON layer also decreases the interface trap charges and improves the interface quality. The leakage current density of the sample with oxynitridization obviously reduced with J A = 2.54 × 10 −8 A/cm 2 at a voltage Vg = +1.00 V. Copyright © 2009 John Wiley & Sons, Ltd.