Thermal oxidation of outdiffusing SiO with permeating O2 in a SiO2 film studied by angle-resolved X-ray photoelectron spectroscopy

The growth and decomposition kinetics of very thin oxides on Si(001) surfaces were investigated by reflection high-energy electron diffraction combined with Auger electron spectroscopy (RHEED-AES) to monitor the reaction rates of oxide growth and decomposition in real time, and changes in surface structure and interface morphology simultaneously. The oxides prepared by stopping the second oxide layer growth at various coverages following the first oxide layer growth by Langmuirtype adsorption at 500 C under an O 2 pressure of 2:6 Â 10 À4 Pa were isothermally annealed by increasing temperature from 500 to 666 C at the same time that O 2 gas was quickly evacuated. It was observed that (1) oxide thickness continued to decrease significantly as measured on the basis of changes in O KLL Auger electron intensity ÁI O-KLL before voids appeared at a nucleation time t N as recognized by the appearance of half-order spots in RHEED patterns, (2) the SiO 2 /Si interface morphology was considerably roughened corresponding to ÁI O-KLL during void nucleation as observed by the evolution of the RHEED intensity of bulk diffraction spots ÁI bulk , (3) the ratio of ÁI bulk to ÁI O-KLL was almost constant, and (4) oxide decomposition rate during void nucleation, which was approximately given by ÁI O-KLL =t N , showed a good linear correlation with the second oxide layer growth rate immediately before starting the decomposition reaction. The good correlation between ÁI O-KLL =t N and clearly indicates that the rate-limiting reaction of the second oxide layer growth is closely related to that of the oxide decomposition during void nucleation. All the above-mentioned observations can be comprehensively interpreted using a reaction model proposed for the rate-limiting reactions of oxide growth and decomposition, in which the point defect generation (emitted Si atoms + vacancies) caused by the strain due to the volume expansion of oxidation plays a crucial role because of the high reactivity of the emitted Si atoms and vacancies with dangling bonds. Under an O 2 atmosphere, both emitted Si atoms and vacancies are the preferential adsorption sites of O 2 molecules in the oxide and at the SiO 2 /Si interface, respectively. The oxide can be decomposed by the emitted Si atoms to produce SiO molecules, which desorb from the surface, leading to oxide removal in vacuum with SiO 2 /Si interface morphology roughening, but may be oxidized within the oxide under an O 2 atmosphere.

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“…[84][85][86] Equation (11) In vacuum, eq. (13) proceeds exclusively to remove oxides from the surface, as illustrated in Fig.…”

Section: Nucleation and Lateral Growth Kinetics Of Voids During Decommentioning

confidence: 99%

Rate-Limiting Reactions of Growth and Decomposition Kinetics of Very Thin Oxides on Si(001) Surfaces Studied by Reflection High-Energy Electron Diffraction Combined with Auger Electron Spectroscopy

Ogawa

Takakuwa

2006

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“…The annealing conditions we used are in the passive oxidation regime, not in the active oxidation regime. 5,14 Following the annealing treatment, the samples were etched in 0.5% HF and 99.5% DDI H 2 O by volume for 2-20 min to remove the silicon oxide layers. Morphologies at the interface were observed in air by tapping-mode AFM immediately after the removal of the as-grown silicon oxide layers.…”

Section: Methodsmentioning

confidence: 99%

“…For surface oxidation, the thermal oxidation can be categorized into two domains-active oxidation ͑etching͒ and passive oxidation ͑oxide growth͒-depending on the oxygen pressure and the oxidation temperature. 14 However, the morphological stability of the growing interface, i.e., the reaction fronts in the growth regime, which governs roughening at the interface, has been not well clarified yet.…”

Section: Introductionmentioning

confidence: 99%

Stability-instability transition of reaction fronts in thermal oxidation of silicon

et al. 2009

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By combining atomic force microscopy and x-ray reflectivity measurements, the morphological evolution at the SiO 2 / Si͑001͒ interface during thermal silicon oxidation was systematically studied as a function of oxidation temperatures. We found that the oxidation-induced roughening switches to smoothening at an oxidation temperature of 1250°C on the oxidation front. The transition is governed by how the strain induced by oxidation is spatially relieved at the interfaces in the silicon oxide bulk film through the interfacial transition layers, which is inevitably important for the strain-relief mechanism.

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“…Takakuwa et al (4) has suggested the SiO emission from the interface by angleresolved X-ray photoelectron spectroscopy (ARXPS) study. Kageshima et al (1) has analyzed the SiO emission by first-principles study, which is, however, based on static energy calculations without considering dynamical effect.…”

Section: Sio Emission In the Si/sio 2 Interfacementioning

confidence: 99%

SiO Emission and Incorporation in Silicon Oxidation Process Using Molecular Dynamics Method

2010

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We investigated the dynamics of oxidation processes with stress relaxation in the Si/SiO2 interface by using variable charge molecular dynamics methods. An SiO molecule is emitted from the Si/SiO2 interface into the SiO2 region in order to release the accumulated stress in the interface. The emitted SiO molecule moves into the SiO2 network having Si dangling bonds. The SiO molecule is completely incorporated into the SiO2 network after an oxygen atom (oxygen vacancy) diffuses to be bonded with these Si dangling bonds.

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Thermal oxidation of outdiffusing SiO with permeating O2 in a SiO2 film studied by angle-resolved X-ray photoelectron spectroscopy

Cited by 58 publications

References 15 publications

Rate-Limiting Reactions of Growth and Decomposition Kinetics of Very Thin Oxides on Si(001) Surfaces Studied by Reflection High-Energy Electron Diffraction Combined with Auger Electron Spectroscopy

Rate-Limiting Reactions of Growth and Decomposition Kinetics of Very Thin Oxides on Si(001) Surfaces Studied by Reflection High-Energy Electron Diffraction Combined with Auger Electron Spectroscopy

Stability-instability transition of reaction fronts in thermal oxidation of silicon

SiO Emission and Incorporation in Silicon Oxidation Process Using Molecular Dynamics Method

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