Oxidation Of Si Surface Research Articles

Ultra‐Thin Strain‐Relieving Si1−xGex Layers Enabling III‐V Epitaxy on Si

AbstractThe explosion of artificial intelligence, the possible end of Moore's law, dawn of quantum computing, and the continued exponential growth of data communications traffic have brought new urgency to the need for laser integration on the diversified Si platform. While diode lasers on group III‐V platforms have long‐powered internet data communications and other optoelectronic technologies, direct integration with Si remains problematic. A paradigm‐shifting solution requires exploring new and unconventional materials and integration approaches. In this work, it is shown that a sub‐10‐nm ultra‐thin Si1−xGex buffer layer fabricated by an oxidative solid‐phase epitaxy process can facilitate extraordinarily efficient strain relaxation. The Si1−xGex layer is formed by ion implanting Ge into Si(111) and selectively oxidizing Si atoms in the resulting ion‐damaged layer, precipitating a fully strain‐relaxed Ge‐rich layer between the Si substrate and surface oxide. The efficient strain relaxation results from the high oxidation temperature, producing a periodic network of dislocations at the substrate interface, coinciding with modulations of the Ge content in the Si1−xGex layer and indicating the presence of defect‐mediated diffusion of Si through the layer. The epitaxial growth of high‐quality GaAs is demonstrated on this ultra‐thin Si1−xGex layer, demonstrating a promising new pathway for integrating III‐V lasers directly on the Si platform.

Coatings consisting of Ge particles on nonwettable Si oxide surfaces and their resonance reflection spectra

The dewetting phenomenon that occurs during annealing of Ge films after their deposition on oxidized Si surfaces at room temperature is studied. The agglomeration of Ge films into compact particles begins at temperature as low as 350 °C. The particle shapes become closer to spherical as the annealing temperature is increased to 700 °C. The reflectance spectra of samples coated with dense arrays of compact Ge particles are measured in the wavelength range of 350–1200 nm. They contain two broad minima, at which the reflection decreases by a factor of 5–10, compared to the bare substrate reflection. The minimum in the long-wavelength region of the spectrum is associated with the excitation of magnetic and electric dipole resonances in individual Ge particles. The appearance of a deeper minimum in the short-wavelength region can be attributed to the excitation of quadrupole resonant modes in combination with the effect of small interparticle spacings. The coatings from the thus obtained particles exhibit strong and broadband antireflection properties.

Controlled surface oxidation of mesoporous silicon microparticles to achieve a stable Si/SiOx anode for lithium-ion batteries

Silicon (Si) is the most promising next-generation anode material for lithium-ion batteries. However, it often suffers from a fast capacity fading due to the large volume changes during the lithiation/delithiation resulting in electrical contact loss between different components of the anode and eventually in battery fading. Mesoporous structure of silicon is a potential material to overcome the issue as the pores could accommodate the volume change during the battery cycling. However, its high surface area can cause continuous parasitic electrolyte decomposition reactions, causing low initial coulombic efficiency (ICE), capacity fading, and battery safety issue. In this study, the surface passivation of mesoporous Si microparticles produced with electrochemical etching and milling was realized through thermal oxidation. The silicon oxide (SiOx) layer generated acted as a protective layer to stabilize the Si surface, thus improving Si electrode performance. Electrochemical characterization showed that the electrode performance of Si/SiOx was strongly correlated with the oxygen content. The Si/SiOx anode delivered a discharge capacity of over 2000 mAh g−1 when the oxygen content was less than 34 wt%, but a much lower capacity when there was higher oxygen content. The best sample (oxidation at 700 °C) showed ICE of 78% and a stable cycling performance for over 180 cycles with a limited capacity of 800 mAh g−1. The results indicate that the appropriate oxidation of mesoporous Si surface to get optimized surface/oxygen content enhances the electrochemical performance of Si anodes essentially.

Effects of post oxidation of SiO2/Si interfaces in ultrahigh vacuum below 450 °C

Growing SiO2 layer by wet-chemical oxidation of Si surfaces before growth of another insulating film(s) is a used method to passivate Si interfaces in applications (e.g., solar cell, photodiode) at low temperatures (LT) below 450 °C. We report on potential of LT ultrahigh-vacuum (UHV) treatments combined with the wet-chemical oxidation, by investigating effects of LT-UHV oxidation after the wet-chemical growth of SiO2 and before growing Al2O3 film on top of SiO2/Si. This method modifies the SiO2/Si and is found to (i) decrease defect-level density, (ii) increase negative fixed charge density, and (iii) increase carrier lifetime for Al2O3/SiO2/p-Si, as compared to state-of-the-art SiO2/p-Si reference interfaces without LT-UHV. X-ray photoelectron spectroscopy shows that the LT-UHV treatment decreases amount of Si+3 oxidized atoms in chemically grown SiO2 and also amount of carbon contamination. In order to pave the way for further tests of LT-UHV in silicon technology, we present a design of simple UHV instrument. The above-described benefits are reproduced for 4-inch silicon wafers by means of the instrument, which is further utilized to make LT-UHV treatments for complementary SiO2/Si interfaces of the native oxide at silicon diode sidewalls to decrease the reverse bias leakage current of the diodes.

Effects of Bias and Temperature on Interface-Trap Annealing in MOS and Linear Bipolar Devices

This article reviews the effects of applied bias and temperature on Si/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interface-trap buildup and annealing rates. Electrical and spectroscopic methods are described to estimate interface-trap densities at oxidized Si surfaces, in MOS capacitors and transistors, and in linear bipolar devices. Illustrative results provide insights into the kinetics and energetics of interface-trap annealing. Interface traps in MOS and linear bipolar devices anneal much more easily at 0 V bias than at positive or negative applied bias. Hydrogen transport and reactions play critical roles in interface-trap buildup and annealing processes. The complex interplay between H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> diffusion and H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> drift is illustrated via coupled experimental and theoretical studies. Interface-trap annealing imposes significant constraints on hardness-assurance techniques. Current MOS standard tests that incorporate accelerated aging at elevated temperature at worst case, static, positive bias enable successful assessment of MOS devices in low-dose-rate environments. However, it is not similarly possible to use elevated-temperature irradiation and/or annealing at worst case, 0 V bias to predict low-dose-rate response for linear bipolar devices and ICs. Temperature-switching during irradiation appears to be a promising approach to address this issue.

Metallization-free silver sinter bonding to silicon via in situ decomposition of silver oxalate

Metallization-free Ag sinter bonding to Si and SiO2 substrates was achieved via the thermal decomposition of Ag oxalate. Ag oxalate generated atomic-scale Ag through decomposition at approximately 200 °C and transformed into sintered Ag. Ag derived from Ag oxalate successfully bonded to Si substrates through close contact formation with Si surface oxide. Similarly, amorphous and α-quartz SiO2 substrates were directly bonded with Ag. These results indicate that the atomic-scale Ag generated on SiO2 contributed to interface formation over a large area. Moreover, the joints of the bare Si chip and metal substrate showed a maximum shear strength of 29 MPa at a bonding temperature of 250 °C and a bonding pressure of 5 MPa. The in-situ generation of Ag through the decomposition of Ag precursors can facilitate the direct bonding of electronic materials, making the proposed method a promising one for electronics applications.

Atomic-Level Material Removal Mechanisms of Si(110) Chemical Mechanical Polishing: Insights from ReaxFF Reactive Molecular Dynamics Simulations.

Reactive molecular dynamics (ReaxFF) simulations are performed to explore the atomistic mechanism of chemical mechanical polishing (CMP) processes on a Si(110) surface polished with an a-SiO2 particle. The Si surface is oxidized by reacting with water before the CMP process, and the O atoms of the oxidized Si surface mainly exist in the form of Si-O- dangling bonds and Si-O-Si bonds. In the CMP process, the insertion of O atoms into the surface, the formation of interfacial Si-O-Si and Si-Si bridge bonds, and the adsorption of H atoms on the surface-saturated Si atoms can all cause the surface bond breakage and even the Si atomic removal. The contributions of the four different kinds of tribochemical wear mechanisms to the surface wear decrease in turn and are much larger than that of mechanical wear. The results indicate that the material removal in the actual Si CMP process is the combined results of multiple atomic-level wear mechanisms. Furthermore, we find that the oxide layer of the Si surface plays an important role in the surface wear mainly by providing O atoms to insert into the surface, rather than by providing additional reaction pathways to form interfacial Si-O-Si bridge bonds. This work provides new and further insights into the process and mechanism of silicon removal during CMP.

Reactive molecular dynamics on the oxidation of passivated H-terminated Si (111) surface: 1-Alkynes vs 1-Alkenes

In this paper, we employed a series of ReaxFF molecular dynamics simulations to study the oxidation of different passivated Si (111) surface, which terminated by 1-Alkynes and 1-Alkenes. Research suggests that the Si substrate was oxidized by the peroxy-like structures (H2O2) during the process. We found that the organic monolayers on the Si surface will make the surface more passivated than the full H-Si surface. In addition, There is higher oxygen consumption in alkenes than the alkynes system. The alkynes system retained more Si-H bonds than alkenes system. And we found more SiOSi and SiOH bonds in the alkenes system rather than the alkynes system. Moreover, simulation results indicate that the O2 molecule is more difficult to pass through the alkynes than alkenes monolayers, which is why better passivation could be reached in alkynes system rather than the alkenes system. This study present atomistic insight into the oxidation of different passivated H-terminated Si (111) Surface, which is helpful to optimize the manufacturing process of the semiconductor devices.

Surface cleaning process for plasma-etched SiC wafer

In this paper, we explored a method to remove the contamination and impurities left on SiC surface after plasma-etched process. The stubborn contamination is resulting from fluorochemical caused by plasma-etched process, residue left after stripping Ni metal mask, Ni–O compounds formed by the metal mask with SiC Si surface oxide film and carbon-containing contamination introduced by the process environment. By adding a layer of SiO2 mask between SiC and the original metal mask together with ultrasonic cleaning and oxygen plasma cleaning process, the sample surface roughness was effectively reduced from 1.090 to 0.055 nm. Moreover, this method supplies a valuable reference for solving the problem of surface contamination caused by plasma etched.

Light transmission and internal scattering in pulsed laser-etched partially-transparent silicon wafers

Continuing trend in silicon wafer thickness directed at cost reduction approaches basic boundaries created by: (a) mismatch between Al paste and Si wafer thermal expansion and (b) incomplete optical absorption. With its symmetrical front and back electrical contacts, the bifacial solar cell setup reduces stress due to mismatch thermal expansion, decreases metal use and increases high temperature efficiency. Efficiency improvement is accomplished in bifacial solar cells by capturing light from the back surface. Partially transparent wafers provide an option to improve near-infrared radiation absorption within Si wafer. To fully absorb optical radiation, three-dimensional texture of these kinds of wafers is essential. Pulsed laser interactions, thermal oxidation, and wet chemical etching are included in this research. A feature of its energy and pattern setup is the interaction of pulsed laser with Si, running at 1.064 μm wavelength and micro-second length. Two experimental settings were explored: (a) post-laser chemical etching with potassium hydro-oxide etching with thermal oxide as etching mask and (b) post-laser heat Si surface oxidation. Due to fast melting and recrystallization, laser pulsed processing inherently produces its own texture. Some of these spherically-shaped, randomly focused characteristics improve inner scattering and boost near-infrared absorption within the wafer. These characteristics are separated during chemical etching with the thermally-grown oxide layer as an etch mask. Comparison of optical absorption in both surfaces shows almost a rise in the magnitude of absorption in non-etched surfaces. Detailed optical (optical microscope and IR absorption), morphological (field emission scanning electron microscope) and heat imaging (far IR camera) analyses were performed to comprehend physical processes that contribute to near-IR absorption improvement. Such kinds of partially-transparent, three-dimensional textured Si wafers are anticipated to discover applications for bifacial solar cells as substrates.

Assessment of clean H2 energy production from water using novel silicon photocatalyst

Nanosheets of silicon have attracted a great deal of attention due to its tunable optical and electronic properties. However, the development of facile and easily scalable synthesis process has remained a great contest. Endeavor has been made in this research to find a waste inferred effective photocatalyst to deliver hydrogen (H2) through visible light responsive water splitting. One-pot solid phase reaction was applied to synthesis catalyst and adopted ultrathin structure. The photocatalytic efficiency of catalyst was examined by XRD, XPS, and UVeVIS absorption spectra, PL, FESEM, HRTEM and EDX. The HRTEM and FESEM images revealed the interconnected nanosheets with Si having the average thickness of 5 nm and their band gaps were 2.3e2.5 eV corresponding to the absorption of visible light range. The H2 production rate on photocatalyst was originated to 3200 mmol h�1 without utilizing any conciliatory electron givers, voltage or pH alteration, which beats the Pt, Ru, Rh, Pd and Au stacked photocatalyst ever detailed up until this point. The significant increase in photocatalytic activity could be the fast charge migration and separation from the silicon-hydrogen and siliconhydroxyl bonds on Si surface and facilitation of charge separation could results from the multiple reflections of visible light on ultrathin nanosheets. It has been confirmed that the electron/hole recombination rate in ultrathin nanosheets of Si declined due to the oxidation of Si surface. It would be presumed that the approach of surface chemistry of silicon could not be limited towards the photocatalytic water splitting and could be applicable to remedy water pollution.

Influence of Selective Surface Oxidation of Si and Mn on Fe–Zn Alloying Reaction on Hot-rolled Steel Sheets

The Fe–Zn alloying reaction and selective oxidation behavior of 0.7 mass% Si-1.15 mass% Mn added hot-rolled steel annealed at 600–800°C were investigated by comparison with those of cold-rolled steel. The Fe–Zn reactivity of the hot-rolled steel improved from 600°C to 700°C but deteriorated from 700°C to 800°C. Above 700°C, the amount of Fe–Si–Mn oxide on the steel surface increased with increasing temperature, and this oxide deteriorated Fe–Zn reactivity. Below 700°C, a thin layer of Fe oxide on the steel surface deteriorated Fe–Zn reactivity. This oxide layer was reduced by Si and Mn that diffused from the steel substrate. Therefore, as the temperature increased from 600°C to 700°C, Fe–Zn reactivity improved due to the formation of reduced iron on the steel surface. In the case of the cold-rolled steel, the same selective oxidation behavior and reduction mechanism of the Fe oxide were also confirmed, and as a result, the Fe–Zn reactivity of the cold-rolled steel showed behavior similar to that of the hot-rolled steel. However, the Fe–Zn reactivity of the cold-rolled steel improved at a lower temperature than that of the hot-rolled steel. This can be explained by the faster diffusion rates of Si and Mn in the cold-rolled steel than in the hot-rolled steel. That is, reduction of the surface Fe oxide layer by diffused Si and Mn proceeded at a lower temperature, and as a result, the Fe–Zn reactivity of the cold-rolled steel also improved at a lower temperature.

Surface oxidation of amorphous Si and Ge slanted columnar and mesoporous thin films: Evidence, scrutiny and limitations for infrared optics

Issues on the superficial oxidation of mesoporous amorphous silicon and germanium photonic layers generated at oblique angles are reported. Such films were designed to improve the transmittance of optical elements over the mid-IR window (3.6–4.9 μm) by removing the light reflection. These nanostructures were deposited on silicon substrates by e-beam evaporation at room temperature. IR ellipsometry and spectrophotometry studies combined with models based on effective medium approximations predicted the presence of silicon or germanium oxides. Such oxidation was evidenced by combining X-ray photoelectron spectroscopy and advanced (scanning-)transmission electron microscopy studies based on energy-dispersive X-rays and electron energy-loss spectroscopies. Both techniques also allowed to prove the formation of core-shell-type architectures consisting of pure Si or Ge surrounded by oxidized species, even for a Ge layer subsequently capped with a dense MgF2 coating. The different approaches used for preparing electron transparent specimens (tripod polishing and focused ion-beams) confirmed a fast oxidation of the Ge nanocolumns even for short air exposure periods, and allowed comparing it with the level of oxidation promoted from other pollutant sources. This work sheds light on the spontaneous undesired oxidation in Si or Ge slanted nanorods which can diminish the performances and limit further development of optical devices.

Thermal-mechanical coupling effect on initial stage oxidation of Si(100) surface

The initial stage oxidation of biaxially strained Si(100) at temperatures ranging from 300 K to 1200 K has been investigated by Reactive Force Field Molecular Dynamics simulations. We reported that the oxidation process involving the reaction rate and the amount of absorbed O atoms could be enhanced by the coupling effect of higher temperatures and larger external tension. By fitting the simulation results, the relationship between absorbed oxygen and the coupling of temperature and strain was obtained. In probing the mechanism, we observed that there was a ballistic transport of O atoms, displaying an enhancement of inward penetration by external tension. Since such an inward transport was favored by thermal actuation, more O atoms penetrated into deeper layers when the 9% strained Si oxidized at 1200 K. Moreover, the evolution of stress in the surface region during the oxidation process was discussed, as well as the related oxide structure and the film quality. These present results may provide a way to understand the thermally-mechanically coupled chemical reactions and propose an effective approach to optimize microscale component processing in the electronic field.

Influence of Selective Surface Oxidation of Si and Mn on Fe-Zn Alloying Reaction on Hot-rolled Steel Sheets

Influence of Selective Surface Oxidation of Si and Mn on Fe-Zn Alloying Reaction on Hot-rolled Steel Sheets

(Invited) Materials Selectivity in Atomic Layer Etching of SiO2, Si, and Si3N4 Using Plasma Process Sequences

Using steady-state Ar plasma in conjunction with periodic injection of a defined number of C4F8 molecules and synchronized plasma-based Ar+ ion bombardment enables controlled removal of SiO2 layers with a thickness in the Angstrom-range.1 The physical sputter rate of SiO2 vanishes for Ar+ ion bombardment with a maximum ion energy of 20 eV and lower, whereas for a fluoroccarbon-coated SiO2 surface, chemical modifications of the SiO2 surface are induced by low energy ion bombardment and SiO2 etching is initiated. In this work we examined SiO2:Si and SiO2:Si3N4 etching selectivity and the roles of maximum ion energy, etching step length (ESL), FC surface coverage, and fluorocarbon precursor selection in controlling these. By optimization of ALE process parameters, e.g. low ion energies, ESL, and FC film deposition per cycle, highly selective SiO2 to Si3N4 etching can be achieved for conditions where FC selectively accumulates on Si3N4 surfaces.2 Surface oxidation of Si takes place during the Ar+ ion bombardment step, and makes it more difficult to achieve abrupt and highly selective removal of thin SiO2 layers from Si. Mechanism of the observed ALE behaviors will be discussed using real-time and post-plasma surface analysis data. 1 D. Metzler, R. Bruce, S. Engelmann, E. A. Joseph, and G. S. Oehrlein, J. Vac. Sci. Technol. A 32, 020603 (2014). 2 C. Li, D. Metzler, C. S. Lai, E. A. Hudson, and G. S. Oehrlein, J. Vac. Sci. Technol. A 34, 041307 (2016). * I gratefully acknowledge the essential contributions and collaboration of Kang-Yi Lin, C. Li, D. Metzler, S. Engelmann, R. Bruce, E. Joseph , C. S. Lai, and E. A. Hudson on which this talk is based. Additionally, funding from Semiconductor Research Corporation (No. 2017-NM-2726), National Science Foundation (CBET-1134273), and US Department of Energy (DE-SC0001939) is thankfully acknowledged.

Potential changes and chemical bonding features for Si-MOS structure as evaluated from HAXPES analysis

An Au/SiO2/Si MOS structure was fabricated by the thermal oxidation of H-terminated Si(100) surface and the electrode formation, and hard X-ray photo-emission spectroscopy (HAXPES) measurements of MOS structure under the different applied bias conditions were performed systematically to investigate the potential distribution such as the band bending in the MOS structure and the chemical bonding features in the region near the Au/SiO2 interface. And, the measured energy position of HAXPES signals originating from the Au electrode, SiO2, and Si substrate were compared with the calculation results of potential change for ideal MOS structure in consideration of SiO2 thickness and impurity concentration of Si substrate.

Toward the Understanding of Selective Si Nano-Oxidation by Atomic Scale Simulations.

The continuous miniaturization of nanodevices, such as transistors, solar cells, and optical fibers, requires the controlled synthesis of (ultra)thin gate oxides (<10 nm), including Si gate-oxide (SiO2) with high quality at the atomic scale. Traditional thermal growth of SiO2 on planar Si surfaces, however, does not allow one to obtain such ultrathin oxide due to either the high oxygen diffusivity at high temperature or the very low sticking ability of incident oxygen at low temperature. Two recent techniques, both operative at low (room) temperature, have been put forward to overcome these obstacles: (i) hyperthermal oxidation of planar Si surfaces and (ii) thermal or plasma-assisted oxidation of nonplanar Si surfaces, including Si nanowires (SiNWs). These nano-oxidation processes are, however, often difficult to study experimentally, due to the key intermediate processes taking place on the nanosecond time scale. In this Account, these Si nano-oxidation techniques are discussed from a computational point of view and compared to both hyperthermal and thermal oxidation experiments, as well as to well-known models of thermal oxidation, including the Deal-Grove, Cabrera-Mott, and Kao models and several alternative mechanisms. In our studies, we use reactive molecular dynamics (MD) and hybrid MD/Monte Carlo simulation techniques, applying the Reax force field. The incident energy of oxygen species is chosen in the range of 1-5 eV in hyperthermal oxidation of planar Si surfaces in order to prevent energy-induced damage. It turns out that hyperthermal growth allows for two growth modes, where the ultrathin oxide thickness depends on either (1) only the kinetic energy of the incident oxygen species at a growth temperature below Ttrans = 600 K, or (2) both the incident energy and the growth temperature at a growth temperature above Ttrans. These modes are specific to such ultrathin oxides, and are not observed in traditional thermal oxidation, nor theoretically considered by already existing models. In the case of thermal or plasma-assisted oxidation of small Si nanowires, on the other hand, the thickness of the ultrathin oxide is a function of the growth temperature and the nanowire diameter. Below Ttrans, which varies with the nanowire diameter, partially oxidized SiNW are formed, whereas complete oxidation to a SiO2 nanowire occurs only above Ttrans. In both nano-oxidation processes at lower temperature (T < Ttrans), final sandwich c-Si|SiOx|a-SiO2 structures are obtained due to a competition between overcoming the energy barrier to penetrate into Si subsurface layers and the compressive stress (∼2-3 GPa) at the Si crystal/oxide interface. The overall atomic-simulation results strongly indicate that the thickness of the intermediate SiOx (x < 2) region is very limited (∼0.5 nm) and constant irrespective of oxidation parameters. Thus, control over the ultrathin SiO2 thickness with good quality is indeed possible by accurately tuning the oxidant energy, oxidation temperature and surface curvature. In general, we discuss and put in perspective these two oxidation mechanisms for obtaining controllable ultrathin gate-oxide films, offering a new route toward the fabrication of nanodevices via selective nano-oxidation.

Surface Oxide Protection of Si(111) in Solution by the Surfactant Molecules

It has been attempted to immobilize organic mono layer on semiconductor surface as functional materials. Silicon surface was especially noticed to develop highly efficient and functional devices, and the silicon devices were expected for the immobilized surface with organic layer. Then we have attempted the immobilization by the mono layer on the hydrogen terminated silicon surface with the alkyl base indicated hydrophobic by using a surfactant. We have observed interactions of immobilized molecules and organic molecules adsorbed on hydrogen terminated Si(111), which is aerosol OT as known surfactant and 4-cyanophenol as shown amphipathic molecule. The aerosol OT inhibited oxidation of Si(111) surface by adsorption to the hydrogen terminated surface to indicate hydrophobic. The 4-cyanophenol made the surface oxide by adsorption, and was desorbed by forming hydrophilic Si surface. In the case of the mixed solution by the aerosol OT and 4-cyanophenol, the aerosol OT controlled the surface oxidation on the hydrogen terminated Si against the 4-cyanophenol.

Enhancement of SiO2/Si(001) interfacial oxidation induced by thermal strain during rapid thermal oxidation

Rapid thermal oxidation, in which samples are intensely heated to a preset temperature, is used to grow silicon oxide on Si substrates while avoiding significant diffusion of impurities into the substrate. In previously proposed reaction models for rapid thermal oxidation, the oxidation rate is only determined by the temperature and O2 pressure. Therefore, it is believed that the rate of oxidation at a preset temperature is independent of the initial substrate temperature. In this study, the interfacial oxidation reactions that follow Si(001) surface oxidation were observed using real-time Auger electron spectroscopy. Interfacial oxidation was enhanced when the substrate temperature was increased from temperature T1 to temperature T2 at the end of Si(001) surface oxidation. As a result, strong T1 and T2 dependences of the interfacial oxidation rate were observed. The interfacial oxidation rate at T1 = room temperature was more than 10 times higher than that at T1 = 561 °C, even for the same T2 (682 °C). A...