DocumentCode :
846920
Title :
Comparison of SiO2 and HfO2/SiO2 gate stacks electrical behaviour at a nanometre scale with CAFM
Author :
Blasco, X. ; Nafría, M. ; Aymerich, X. ; Vandervorst, W.
Author_Institution :
Dept. d´´Enginyeria Electron., Univ. Autonoma de Barcelona, Bellaterra, Spain
Volume :
41
Issue :
12
fYear :
2005
fDate :
6/9/2005 12:00:00 AM
Firstpage :
719
Lastpage :
721
Abstract :
The electrical behaviour of a SiO2 gate layer and a HfO2/SiO2 gate stack are studied at the nanometre scale by means of CAFM. The leaky spot (LS) and breakdown (BD) spot sizes, the post BD current-voltage (I-V) characteristics and the topography features have been compared. LS of ∼600-700 nm2 and BD sizes of 1000-3000 nm2 are measured for the SiO2 layer and the HfO2/SiO2 stack. Post BD I-V characteristics reveal that, for SiO2, I-V curves are well grouped and CAFM compliance is always reached for Vgate<0.5 V. For the HfO2/SiO2 stack, I-V curves show very much dispersion, and the Vgate needed to reach the compliance is larger. Therefore, the high-k layer reduces the severity of the BD event. Even so, a few times the HfO2/SiO2 stack BD spots exhibit I-V characteristics as conductive as SiO2 BD spots.
Keywords :
atomic force microscopy; dielectric materials; hafnium compounds; semiconductor heterojunctions; silicon compounds; CAFM; HfO2-SiO2; breakdown spot; conductivity atomic force microscopy; current-voltage characteristics; electrical behaviour; gate layer; gate stack; high-k layer; leaky spot; nanometre scale;
fLanguage :
English
Journal_Title :
Electronics Letters
Publisher :
iet
ISSN :
0013-5194
Type :
jour
DOI :
10.1049/el:20050805
Filename :
1441132
Link To Document :
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