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The evolution of different oxidation states during thermal oxidation of (100) oriented Ge substrate was investigated with X-ray photoelectron spectroscopic analysis. The thermally grown oxides in the temperature range of 380 to 500°C were found to consist of four different oxidation states of Ge, namely, Ge1+, Ge2+, Ge3+, and Ge4+. The fractional composition of the oxide species is seen to be dependent on oxidation temperature. Spectroscopic depth profiling reveals variation of oxide composition along the depth of the oxide layer with a large concentration of GeO2 near the oxide surface and a large concentration of suboxides near the oxide/Ge interface. The results obtained in the investigation will help in achieving greater insight into the thermal oxidation process of Ge

Ag–36.35 wt.% Zn and Ag–38.50 wt.% Zn–0.60 wt.% Al were oxidised in air at 450–650 °C up to 48 h. The oxidation kinetics of both alloys were parabolic with the lower rate constant for the latter alloy. After oxidation for 48 h, thermal oxide scale on Ag–36.35 wt.% Zn was ZnO at all studied temperatures. When 0.60 wt.% Al was added to Ag–38.50 wt.% Zn, ZnO and ZnAl 2 O 4 were formed at all studied temperatures. Al 2 O 3 was evidently observed at 550 and 650 °C. The formation of Al-containing oxides helped reduce the oxidation rate of Ag–38.50 wt.% Zn–0.60 wt.% Al.

The surface morphology of GaSb was investigated by changing growth conditions such as thermal oxide desorption temperature, growth temperature, and growth step by solid source molecular beam epitaxy. At high temperature growth, the pits caused by the thermal oxide desorption remained in the GaSb buffer layer surface, while the surface was sufficiently flattened. At low temperature growth, the pits disappeared, while the surface was not enough flattened even in the case of step-flow mode growth. Since the pits disappeared at lower growth temperature regardless of the growth mode, this behavior might be explained by the Ga migration length depending on the growth temperature. By applying two-step high/low temperature growth, where both growth steps proceed in step-flow mode, flat, a pit-free GaSb buffer surface could be obtained.

(Attention for corrosion science, the abstract must not exceed more than 100 words) In this research, first a multi-analytical approach was carried out to propose a mechanistic model for the formation of the thermal oxide film on low Cr stainless steel. It describes the effects of kinetically and thermodynamically driven phenomena on the growth of a Fe-Cr complex oxide film at 950℃. Second, the behavior of the thermal oxide film in the presence of fluoride ions, as a relevant pickling agent in conversion treatment, was investigated. It was shown that fluoride ions enter the oxide film and form a complex with Fe and preferentially dissolve hematite islands through a complexation mechanism.

This paper reports on the effect of oxidation on fracture behavior of single crystal silicon (SCS). SCS specimens were fabricated from (1 0 0) silicon-on-insulator wafer with 5-μm-thick device layer and oxide layer were thermally grown. Quasi-static tensile testing of as-fabricated, oxidized and oxidized layer removed specimens was performed. The fracture origin location transited from the surface to silicon/oxide interface and inside of silicon. The transition may be caused by surface smoothing, thickening oxide layer and formation of oxide precipitation defects in silicon during oxidation. The radius of the oxide precipitation defects was estimated, which is well agreed with the fracture-initiating crack sizes.

The effects of NO and forming gas post oxidation annealing treatments on the interfacial properties and reliability of thermal oxides grown on n-type 4H-SiC (0001) Si face have been investigated in this study. The results show that forming gas annealing (FGA) treatment has limited effect on interface trap density ( D it ) while it results in an improvement of the insulating properties of thermal oxide with uniform high FN barrier height (2.56 eV), high field-to-breakdown (10.71 MV/cm) and charge-to-breakdown (0.078 C/cm 2 ). On the other hand, NO annealing causes a drastic reduction in D it in the entire energy level, but in the case of reliability, it is not so effective as FGA, with lower barrier height (2.52 eV), field-to-breakdown (10.08 MV/cm), charge-to-breakdown (0.025 C/cm 2 ) and worse uniformity of oxide. The combined NO&FGA treatment was also studied. It leads to a significant reduction in interface trap density further, especially in deep energy level ( E C -E T ≥ 0.4 eV). As for reliability, it brings about uniform barrier height (2.69 eV), field-to-breakdown (10.15 MV/cm) and charge-to-breakdown (0.024 C/cm 2 ). Taking interfacial properties and reliability into account, combined NO&FGA treatment is a promising POA technique for fabrication of high-quality SiC MOS devices.

The impedance behavior of pre-oxidized iron in liquid lead-bismuth eutectic (LBE) at 200 °C is studied using electrochemical impedance spectroscopy. The structures and resistance of oxide grown on iron oxidized in air at different temperatures and durations are compared. The results show that the resistance of the oxide film increases with increasing oxidizing temperature, due to the formation of a thicker scale and fewer defects. At the same temperature (600 °C), increasing the oxidation time can also reduce the defect concentration in the oxide film and improve the impedance of the oxide scale in LBE.

The thickness influence of thermal oxide layers on Si(111) substrates on the formation of self-catalyzed InAs nanowires (NWs) grown by metal-organic chemical vapor deposition (MOCVD) has been investigated. It is found that the thickness of the thermal oxide layer has a strong effect on the morphological characteristics of InAs NWs formed on the Si substrates. In particular, within a suitable thickness range, it is possible to achieve vertical InAs NWs with a uniform distribution of their positions, lengths and diameters. In addition, growth on the thermal oxide layer both improves the morphology of the NWs, and suppresses the frequently observed parasitic islands compared to growth on bare Si. A growth model, which is based on the diffusion length of adatoms, the growth temperature, the thickness of thermal oxide layer, the size and the density of thermal oxide holes, has been developed to explain the formation of the self-catalyzed InAs NWs on the Si substrate with a thermal oxide layer.

International audience; In the present work, mechanical features of different thermal oxide films growing on metals have been investigated at different temperatures. An adapted model is performed to describe the stresses evolution within the oxide films. These predictions are compared with experimental results obtained by different experimental techniques. In order to obtain some accurate mechanical characteristic parameters of the system, both an asymptotic approach and an optimization procedure have been developed and presented through a general methodology. In respect to the chosen assumptions, the present model enables to give a precise mechanical description of each considered layer.© 2013 Elsevier B.V. All rights reserved.

International audience; In the present work, mechanical features are investigated in the case of ZrO2 thermal oxide films growing on a Zr alloy at the temperature of 550°C. The effects of a nanocrystallisation treatment on high temperature oxidation of a zirconium alloy are specifically studied. High temperature oxidation is performed in order to show benefits of such a nanocrystallisation on corrosion resistance and its influence on the mechanical fields. Experimental results obtained by Raman spectroscopy give the growth stress evolution in ZrO2 films. Using a modelling of the system, both asymptotic forms and an optimization procedure are developed to determine the mechanical characteristic parameters of the system. © 2012 Elsevier Ltd.

Mechanical features have been investigated in the case of α - Cr 2 O 3 thermal oxide films growing on NiCr 30 alloy in the temperature range 700–900 °C. From previous experimental results obtained by Raman spectroscopy and giving the growth stress evolution in α - Cr 2 O 3 films, and based on a modelling of the system, both asymptotic forms and an optimization procedure have been developed which give values for the mechanical characteristic parameters of the system and also its evolution with the oxidation temperature.

A theoretical study of the structural and electronic properties of the interfaces between a set of III-V compound semiconductors of technological interest and their native oxides is reported. First-principles techniques have been applied to model the reaction of oxidation of the GaAs(001)-@b2(2x4) surface and to generate a set of representative models of the atomic structure of a thermally grown GaAs/native oxide interface. The obtained models have been extended to the InAs/ and In"0"."5Ga"0"."5As/native oxide interfaces case. The impact of indium on both the structural changes occurring during the oxidation of the substrate and the resulting electronic properties has been quantified.

Electrochemical oxidation of diethylenetriamine (DETA) charged with 0.1 M LiSO3CF3, leads to a polymeric coating (polyethyleneimine film: PEI) on the porous silicon (PS) surface. The obtained passivated electrode is characterized through IRTF spectrometry and through C(V) curves on PS/PEI structures showing good insulating properties of the PEI film. The passivated electrode presents a linear pH sensitivity close to 62 mV per pH unit. Such sensitivity is higher compared to flat PEI passivated silicon electrode. The results were fitted with the generalized site-binding theory and the following parameters were found: the surface site density Ns was found to be equal to 3.6 × 1016 cm− 2 and pKH (KH acido-basic constant of the amino group) is − 5.54.

The kinetics and mechanism of probe-induced oxide growth on an octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) passivated native-SiO2/Si surface have been investigated using atomic force microscopy (AFM). It was found that oxidation strongly depends on tip polarity and the local chemistry of OTS molecules. At negative tip voltage, oxide grows and the oxidation involves a decomposition and depletion of OTS SAM. While under positive tip bias, OTS molecules are partially degraded. The dielectrical properties of the oxide were characterized by I–V measurements using current sensing AFM. The barrier height of AFM grown oxide, in comparison with thermal oxide and OTS SAM, was determined. Current spikes relating to the release of single charge were also observed on the I–V curves of AFM oxide.

The inverted blister test was used to study the adhesion of chromium-rich oxide scales thermally grown on several ferritic stainless steels. With this technique, a quantitative determination of the adhesion energy of the oxide on its substrate was possible. The adhesion energy is found to vary between 3 and 170 J m−2 depending on the specimens. It appears that the parameters influencing adhesion are oxide thickness and the nature of the minor alloying elements present in the alloy. The microstructural observation of both sides of the oxide/alloy interface after debonding provides important information on adhesion and spallation.

Most recently low-dose (4E17 ions/cm2) SIMOX technology has been developed in order to restrain the dislocation density and the production cost. However, in- and out-diffusion of oxygen and internal oxidation (ITOX) phenomena have never been understood during high-temperature annealing process as yet. In this study, we use the sample, which was implanted 18 O + with the dose of 4E17 ions/cm2 into silicon substrate and then non-oxidizing anneal was done at around 1300 °C. As the results, it was proven that the diffusion of oxygen into thermal oxide layer above 1300 °C was not in agreement with the Deal–Grove theory. The mechanism of oxygen in- and out-diffusion in SIMOX wafer is discussed.

Recently, interest has risen in silicidation through oxide (SiTOx). For CoSi2, it has been reported that the presence of a thin, chemically grown oxide results in the formation of epitaxial CoSi2. The method is known as oxide mediated epitaxy (OME). In this paper, results are reported on CoSi2 formation in the Co/SiO2/Si, Ti/Co/SiO2/Si and Co/Ti/SiO2/Si systems for both chemically and thermally grown oxides. Chemically grown oxides were formed in HCl, NH4OH and HNO3-based solutions. The influence of the type and thickness of the oxide on the silicidation reaction is discussed. In the presence of a thin HCl oxide, the reaction proceeds in a layerwise fashion. For thicker oxides (both HNO3 and thermal oxide), the reaction is initiated at weak spots in the oxide layer. We have observed that Ti can reduce the interfacial oxide, especially if the Ti is deposited directly on top of the oxide (Co/Ti/SiO2/Si structure). This is the case both for chemically and thermally grown oxides, although the thicker the oxide, the thicker Ti layers are needed. In the presence of a Ti capping layer (Ti/Co/SiO2/Si), Ti diffuses through the unreacted Co towards the SiO2. In case of a thin oxide, the supply of Ti that can reach the oxide by fast grain boundary diffusion is sufficient for reduction of the SiO2. In case of a thicker, thermal oxide, Co3Ti is formed.

The purpose of this contribution is to give an overview of silicon-on-insulator (SOI) technology with emphasis on the fabrication of SOI substrates and their material properties. Although the concept of SOI has been around for several decades, only recent material science advances made the fabrication of thin-film substrates possible whose material quality is comparable to bulk wafers. SIMOX wafers benefitted from lowering the oxygen dose needed for ion-beam synthesis of buried oxide layers and optimisation of the thermal annealing cycles. Through improved thinning technologies, the wafer-direct-bonding approach for the burial of thermal oxide layers became competetive for thin-film SOI, especially when complemented with the salvaging of the “sacrificial” wafer.

The traps at the interface of directly bonded silicon-on-insulator structures have been investigated for the first time using a contactless and nondestructive computer controlled microwave transient photoconductivity method. It is shown that during bonding process electrically active states appear at the interface. The values of activation energies and capture cross-sections of charge carriers are obtained which are associated with the presence of the interface states similar to those at the Si/thermal oxide interface.

We report on the influence of the chemical etching in the step bunching formation on GaAs (100) 0.2° off and GaAs (100) 2° off toward surfaces after the oxide desorption process of the substrates at high temperatures under an H 2 ambient. The step bunches were observed by in-air atomic force microscopy. Our results reveal that step bunches were formed only on chemically etched samples desorbed under an As 4 overpressure using H 2 as the carrier. When GaAs substrates without chemical etch were deoxidized the step bunches were not observed in despite of the H 2 /As 4 presence. From the results we conclude that the chemical etching strongly influence the step bunching formation.

The periodic changes in surface microroughness of thermal oxide films formed on Si(100) surface with a period in thickness of 0.18 nm were discovered using a noncontact-mode atomic force microscope. This observation combined with structural studies of the interface implies that the layer-by-layer oxidation occurs locally.

The ability to form a thermal oxide on SiC is seen as being of key importance in the practical realisation of high power switching devices. To date efforts to reproduce the refined process technology possible in Si has met with limited success in SiC. In this paper we review current understanding of the oxidation technology used in SiC.

The aim of this experiment was to explore the possibility to convert the Si-overlayer of a SIMOX wafer into 3C-SiC by carbon implantation. In a first attempt carbon was implanted at a temperature 1030°C and energy 100 keV to a dose of 2.5 × 1017 C+ cm−2. The SIMOX was covered by a thick thermal oxide. Cross-section TEM observations on the implanted specimen reveal that carbon is concentrated mainly at the Si/SiO2 interfaces at the front and back face of the Si-overlayer forming continuous but highly defected 3C-SiC layers which are in epitaxial relation with the Si matrix. The implanted carbon has the tendency to migrate from the SiO2 and Si to the SiO2/Si interfaces to form SiC there.

We show here that the oxide-thickness dependence of the s-polarized SHG from Si(111) covered with a thick thermal oxide is completely described by multiple reflections in the oxide film. For the p-polarized response, a strong enhancement with thickness is observed, which cannot be explained in this way. These measurements show that one should be cautious in analyzing the SHG from a buried interface, and carefully take into account the linear optics involved.

Comparative studies of the oxide charge trapping and interface state generation in n-6HSiC SiO 2 and Si SiO 2 structures were performed using electron/hole photo-injection. The thermal oxide on SiC was found to have a comparable density of electron traps and even lower density of hole traps than that one on Si. In contrast to the Si SiO 2 system, the electron injection in the oxide on 6HSiC produces a large density of deep acceptor interface states, which are stable in the temperature range below 300 °C.

The analysis of SIMOX structures obtained after successive implantation and annealing processes has been performed by Raman scattering and FTIR spectroscopy measurements. The experimental data show the presence of tensile stress in the top Si layer of the SIMOX structure, as well as likely compressive stress below the buried oxide layer. Tensile stress in the top Si layer is higher after the third implantation step, which correlates with the lower concentration of structural defects observed by TEM. Annealing this sample leads to an essentially stress-free Si structure. Measurements performed directly on the BOX suggest compressive stress below this layer, which is also relieved after annealing. FTIR data also confirms the formation of a stoichiometric buried oxide which shows some structural differences when compared to a thermal oxide.

The electrical properties of thin dual-layer silicon oxide films have been studied. These stacked oxide films consist of reoxidized low pressure thermal oxide, and at low pressure, chemically vapor-deposited high temperature oxide prepared by an intra-chamber process without breaking the vacuum. Analysis of these dual-layer oxides reveals lower defect densities as well as higher breakdown field strengths and better charge-to-breakdown characteristics than conventionally produced dual-layer or thermal oxides. Interface quality and stability cannot be improved by stacking silicon oxide films.

The second harmonic (SH) generation method has been applied to the study of the silicon-insulator (S-I) interface by in situ control of the etching process of SiO2 thermal oxide and Si3N4 silicon nitride insulator layers. It is shown, that the thin oxide interlayer, adjacent to the Si(111) epitaxial surface (with ∼ 1 nm thickness) exerts high influence on the reflected SH intensity. Various contributions to the nonlinear polarization in the S-I interface such as the static electric field, the inhomogeneous deformation and the crystalline oxide interlayer are considered.

The growth and transport in oxide films formed on (100) Si (p-type) in O2 at 1.33 kPa and 950°C was studied using the 18O/SIMS technique. Samples were oxidized sequentially in 18O2 and 16O2 for times up to 48 h to produce films in the thickness range 2–50 nm. The kinetic data approximate to a linear rate relation apart from an initial more rapid growth region. Sputter profiles of both 18O- and 16-containing species (Si2O+) showed the distribution of each within the thin oxide films. When samples are oxidized first in 16O2 and then in 18O2 the 18O is concentrated in the vicinity of the gas-SiO2 interface and at the Si-SiO2 interface. The concentration at the latter interface increases with increasing time of exposure to 18O2 and predominates at longer times. The SIMS profiles confirm that the principal transport process is inward oxygen diffusion through the oxide during oxidation probably along short circuit paths such as micropores.

Fluorine was impregnated at the Si-SiO2 interface by implanting fluorine ions (19F+) into silicon at low energy (20 keV) to a dose in the range 1011–1015 ions/cm2. Studies were carried out for two cases: first, silicon was oxidised in dry oxygen after 19F+ implantation and second, silicon was implanted with 19F+ after its oxidation to a 207 A thick dry thermal oxide. In both the cases, high frequency capacitance-voltage (HF C-V) measurements show reduction in the midgap interface state density (Nss) nearly by one order of magnitude. Another important observation was that the incorporation of fluorine reduces the oxidation rate of silicon without deteriorating the interface properties.

Thin thermal oxide layers grown on silicon by rapid thermal oxidation and furnace oxidation have been characterized using spectroscopic ellipsometry. Oxide thickness (T) and refractive index (n) were determined independently. The problem of correlation in ellipsometric measurements between n and T is addressed. The results show that the relative oxide density, which is related to n, increases as the layer thickness decreases. For a given layer thickness in the range of approximately 80–200 A, furnace oxides grown at 900 °C generally have a higher density than rapid thermal oxides grown at 1050 °C. The data also indicate that densities were more reproducible for furnace oxides of the same thickness than for rapid thermal oxides.

Using 17 O-enriched thermal oxide on silicon, we have measured the hyperfine interaction between dangling bonds at the (111) interface (P b centers) and oxygen. Our analysis shows that the P b center interacts with a single oxygen atom in the SiO 2 .

The dose repeatability and uniformity of certain low dose implants are of critical importance in optimizing yields in VLSI processes. The need to closely control implant variations motivates the use of instruments to monitor implanted wafers. However, all low dose implant measurement techniques can produce apparent dose repeatability and uniformity variations not related to the ion implanter which will dominate the measurement unless appropriate controls are employed. This investigation identifies several sources of apparent dose variation which must be controlled to obtain precision when using modulated reflectance damage measurements of implanted wafers. The effects of measurement procedure, thermal oxide density, thickness and uniformity on indicated dose when using a boron, × 1012/cm2, 100 keV implant are described. Controls which will allow precise low dose implant characterization are identified.

The morphology and distribution of phases resulting from the thermal oxidation of GaAs at 500 ° C has been investigated by application of high-resolution transmission electron microscopy to cross-sectioned specimens. The oxide layer grown at 500 ° C was found to consist of epitaxial Y-Ga2O3 with hexagonal As precipitates at the interface with GaAs. The evolution of the oxide/GaAs interface morphology is discussed in light of these results.

We have investigated plasma enhanced chemical vapor deposited (PECVD) and thermal oxides using electron spin resonance (ESR). We have been able to show that electron injection into PECVD oxides results in the generation of neutral E′ centers. The E′ center is an unpaired electron on a silicon backbonded to three oxygens. However, in thermal oxides, E′ centers are generated by hole injection, not electron injection; thermal oxide E′ centers are positively charged. Thus, there are fundamental differences in the point-defects in thermally grown and PECVD oxides.

MNOS capacitors (metal-nitrite-oxide-semiconductor) have been used to study the effects of memory oxide growth and post-oxidation annealing conditions on retention and endurance of MNOS devices. Results of this study indicate that write/erase cycling causes a decrease in memory window size after 10 5 cycles, a shift of the memory window center toward more positive values of threshold voltage, and an increase in surface state density for cycling above 10 6 cycles. The retention data presented indicates that the memory window decay rate for ±25 V writing pulses is only a function of the initial window size. The collapse of the memory window to zero volts is predicted to occur after 10 16 sec for native oxide devices and after 10 18 sec for thermal oxide devices. HCl annealing of the memory oxide does not have a significant effect on either endurance or retention.

XPS and spectroscopic ellipsometry combined to chemical etching depth profiling techniques have been used to study the chemical composition of thin oxide films thermally grown on InP(100) in the 250–550°C range. It is shown that oxides are made up of a microscopic mixture of In 2 O 3 and InPO 4 with elemental P at the interface.

The infrared absorption spectra both of ultrathin plasma SiO 2 and of thermal oxide (15–100 nm) treated in RF O 2 plasma are investigated in the wave number range from 400 to 4000 cm −1 . A conclusion is made that the plasma oxide consists of amorphous and different kinds of crystalline phases. The IR spectra of plasma oxide depend slightly on the discharge parameters. The structure of the as-grown thermal oxide, thinner than 40 nm, is shown to have defects and the presence of crystalline phases is observed too. The IR spectra of these oxides are changed significantly after plasma exposure. The influence of RF O 2 plasma on the thermal oxide, thicker than 40 nm, is negligible with respect to structural changes.

Silicon dioxide layers deposited from the vapour phase at low temperatures are extensively applied in integrated circuit technology. Applications include doped oxide diffusion sources, protective layers and cross-over insulators in multilevel metallization systems. In this paper we show the feasibility of obtaining a SiO 2 Si interface whose electrical characteristics closely approach those of thermally grown SiO 2 Si sandwich structures. Interface state densities lying in the low 10 10 cm −2 eV −1 range have been determined from quasi-static C(V) measurements. The results of excess noise measurements made on deposited gate oxide and thermally grown gate oxide MOSFETs are in reasonable agreement with the interface state density measurements. C(V) dispersion and C(V) hysteresis measurements prior to and after exposure to 10 7 rad of 60 Co γ radiation are also presented. Potential applications of low temperature vapour-deposited oxides include the silicon on insulating substrate (SOS) technology where it is generally desirable to minimize high temperature processing steps. Other applications are in the field of impurity profile determinations using the MOS capacitor method. In these applications one desires to measure the original profile without having to deal with the additional complication of the diffusion and redistribution phenomena that occur unavoidably during high temperature thermal oxide growth.

Contact potential measurements by the Kelvin method were performed in vacuum on silicon wafers whose thermal oxide film was etched into the shape of a wedge. A given position along the oxide corresponded directly to a given depth and by scanning a reference electrode stripe across the wafer, information about the distribution of the oxide charge through the thickness was obtained. It was found that the oxide charge was positive and concentrated within a few hundred angstroms of the SiSiO2 interface.

Experimental data are presented for the influence of helium plasma on the electrical properties of Si−SiO 2 structures with dry thermal oxide (d=16−72 nm). It is found that for strongly damaged structures low temperature helium plasma introduces acceptor-type interface states near the conduction band edge and has an annealing effect on the deep acceptor-type states. It has also shown that the initial characteristics of the Si−SiO 2 structures and the gas used are critical for the plasma-forming of both the interface and inversion channel properties.