DocumentCode :
2981592
Title :
The role of water in the radiation response of wet and dry oxides
Author :
Batyrev, I.G. ; Fleetwood, D.M. ; Schrimpf, R.D. ; Ides, S. T Pantel
Author_Institution :
Dept. of Phys., Vanderbilt Univ., Nashville, TN, USA
fYear :
2007
fDate :
10-14 Sept. 2007
Firstpage :
1
Lastpage :
6
Abstract :
We report results of first-principles calculations that explain why radiation-induced interface-trap density increases at a slower rate in wet versus dry oxides in the initial stages of interface-trap buildup. Similar effects are observed in MOS devices after exposure to elevated humidity and temperature or after non-hermetic aging. We explore the possible reactions responsible for passivation of dangling bonds near the Si/SiO2 interface by water and elucidate a new energetically favorable path of the reaction. Prior to irradiation, the passivation of the dangling bonds happens either with formation of Si-H bonds and release of OH complexes, or with formation of Si-OH bonds and the release of H atoms. Both reactions have activation energies of ~0.9 eV and occur rarely at room temperatures. The OH complex is quite mobile, and can migrate along the interface and passivate dangling bonds via the formation of Si-OH bonds. After irradiation and release of protons, the Si-OH and SiH bonds may be formed with lower activation energy through passivation of a positively charged dangling bond by a water molecule. The presence of a hole at the dangling bond causes the resulting passivated SiOH bond and proton to have a lower energy than the initial water and dangling bond, and favors passivation of the dangling bonds. We discuss the relevance of the reactions for modeling the radiation response of wet and dry oxides, aging of MOS devices, and pre-irradiation elevated temperature stress.
Keywords :
MIS devices; ab initio calculations; ageing; passivation; radiation effects; water; H2O; MOS devices; Si-H bonds; Si-OH bond; aging; dangling bonds; dry oxide; first-principles calculations; interface-trap buildup; nonhermetic aging; passivation; preirradiation elevated temperature stress; radiation response; radiation-induced interface-trap density; temperature 293 K to 298 K; water molecule; wet oxide; Aging; Annealing; Charge measurement; Charge pumps; Current measurement; MOS devices; Oxidation; Passivation; Protons; Temperature; Interface traps; dry oxides; first principle calculation; passivation; radiation response; water absorption; wet;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Radiation and Its Effects on Components and Systems, 2007. RADECS 2007. 9th European Conference on
Conference_Location :
Deauville
ISSN :
0379-6566
Print_ISBN :
978-1-4244-1704-9
Type :
conf
DOI :
10.1109/RADECS.2007.5205535
Filename :
5205535
Link To Document :
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