Properties Of Silicon Oxide Films Research Articles

Effect of heat treatment temperature on the properties of silicon dioxide films derived from film-forming solutions

The effect of the heat treatment temperature on the physical properties of sol-gel silicon dioxide films derived from film-forming solutions is investigated experimentally. The dependencies of the thickness of the films, their refractive index, electrical strength, resistivity, etching rate, and the level of internal mechanical stresses on the treatment temperatures in the range from 700 to 1150 °C are obtained. It was found that the dependencies of the electrical strength, the etching rate, and the level of internal mechanical stresses have the sections with the different characters. The transition region between these sections corresponds to the heat treatment temperature equal to 900-950 °C.

Influence of Small-Size Contaminations on Thin Film Structural Properties**Supported by the RFBR under Grant No 17-57-53091, and the National Natural Science Foundation of China under Grant No 11611530687.

An approach for studying the influence of nano-particles on the structural properties of deposited thin films is proposed. It is based on the molecular dynamic modeling of the deposition process in the presence of contaminating nano-particles. The nano-particle is assumed to be immobile and its interaction with film atoms is described by a spherically symmetric potential. The approach is applied to the investigation of properties of silicon dioxide films. Visualization tools are used to investigate the porosity associated with nano-particles. The structure of the film near the nano-particle is studied using the radial distribution function. It is found that fluctuations of film density near the nano-particles are essentially different in the cases of low-energy and high-energy deposition processes.

Effects of Substrate Temperature on the Properties of Silicon Oxide Films by PECVD

Under different growth conditions, silicon Oxide (SiOx) thin films were deposited successfully on Si (100) substrates and glass substrates by plasma enhanced chemical vapor deposition (PECVD). The thickness, refractive index and growth rate of the thin films were tested by ellipsometer. The effects of deposition temperature on the structure and properties of SiOx films were studied using X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) and UV-Visible spectroscopy. The results show that the SiOx films were amorphous at different deposition temperature. The peaks of Si2p and O1s shifted to higher binding energy with temperature increasing. The SiOx films had high transmissivity at the range of 400-900nm. By analyzing the observation and data, the influence of deposition parameters on the electrical properties and interface characteristics of SiOx thin film prepared by PECVD is systematically discussed. At last, SiOx thin film with excellent electrical properties and good interface characteristic is prepared under the relatively optimum parameters.

Synthesis and properties of silicon dioxide films prepared by pulsed laser deposition using ceramic SiO 2 target

Silicon dioxide (SiO 2) thin films were deposited on BK7 substrates by pulsed laser deposition (PLD) method using ceramic SiO 2 targets (C-SiO 2-Ts), which was sintered by solid state sintering. The reason for using C-SiO 2-T instead of the silicon target is to reduce the oxygen-deficiency phenomenon in deposited SiO 2 thin films. The influence of substrate-temperatures, oxygen-pressures and oxygen-plasma-assistance on the properties of synthesized films was studied. X-ray diffraction, atomic force microscopy, ultraviolet–visible–near-infrared scanning spectrophotometry were used to characterize the crystallinity, morphology and optical properties of deposited films. Results show that the root-mean-square roughness of films increased with the increase of oxygen-pressure, substrate-temperature and with the employment of oxygen-plasma. The transmittance of films increased with the increase of oxygen-pressure and decreased with the increase of substrate-temperature and with the employment of oxygen-plasma. Stoichiometric SiO 2 thin film with high optical quality was synthesized at room-temperature and 20 Pa oxygen-pressure using C-SiO 2-T.

Surface properties of silicon oxide films deposited using low-pressure dielectric barrier discharge

The deposition of SiO X films from low-pressure dielectric barrier discharge plasmas has been investigated using tetraethoxysilane (TEOS)/O 2 as the feed gas. Films were analyzed using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), AFM-based nanoindentation/nanowear techniques, and conductive AFM. Film deposition rates and hydrocarbon incorporation in the SiO X film decrease with addition of O 2. High-quality SiO X films with extremely low surface roughness are deposited at high oxidant concertrations. Addition of oxidant to the feed gas leads to a change in the SiO X film structure from precursor-like to a dense SiO X structure. The SiO X films deposited with TEOS/O 2 plasmas were found to have soft surface layers, 0.5–1.5 nm thick, which contribute to an improvement of their field emission properties. The effect of gas phase compositions on the surface properties of the conductive surface layer was discussed.

Effects of the oxygen fraction and substrate bias power on the electrical and optical properties of silicon oxide films by plasma enhanced chemical vapour deposition using TMOS/O2 gas

Thin oxide films are deposited from tetramethoxysilane in an inductively coupled oxygen glow discharge supplied with radio frequency power. The chemical bonding states of deposited films are analysed by Fourier transform infrared spectroscopy. The deposition rate and optical properties are determined from spectroscopic ellipsometry. Capacitance–voltage measurements are performed in MOS capacitors to obtain the electrical properties of the deposited films. With these tools, the effects of the substrate bias power and the oxygen mole fraction in the gas on the properties of the film are investigated. The refractive index first decreases with an increase in the oxygen mole fraction, and then increases again, showing a behaviour opposite to that of the deposition rate. The deposition rate increases with increasing substrate bias power and then saturates, while the refractive index increases slightly with an increase in the substrate bias power. The fixed oxide charge density decreases with increasing oxygen fraction and with increasing substrate bias power, while the interface trap density increases with increasing oxygen fraction and with increasing substrate bias power.

Gas barrier properties of silicon oxide films prepared by plasma-enhanced CVD using tetramethoxysilane

Silicon oxide films were deposited by means of capacitively coupled RF plasma-enhanced CVD using a mixture of tetramethoxysilane and oxygen as source. Chemical compositions and bonding states of the deposited films were analyzed by FTIR and XPS. The absorption bands due to Si–CH 3, Si–H and Si–OH in the FTIR spectra became markedly smaller when the RF power and the fraction of oxygen increased and the total pressure decreased. The optimal oxygen fraction, RF power and total pressure were 50%, 200 W and 10 Pa, respectively, for obtaining pure silicon oxide films. In the films deposited under these optimal deposition conditions, the impurities contaminated from the raw organosilane compound were rarely detectable. Oxygen transmittance of the silicon oxide films greatly depended on their thicknesses and compositions. The oxygen transmission rate of the film prepared under the optimal deposition conditions was 1.3 cm 3/m 2 day atm, far <2 cm 3/m 2 day atm, which satisfies the requirements for industrial products in the field of packaging.

Structure and properties of silicon oxide films deposited in a dual microwave-rf plasma reactor

The characterisation of SiO x thin films deposited from hexamethyldisiloxane in a microwave plasma reactor showed they were carbon containing and porous. With the aim of improving the film quality, the substrate holder was biased with the use of a 13.56-MHz radio-frequency power supply. Results on chemical structure, deposition rate and optical emission spectroscopy are reported. The rf-induced negative bias voltage affected both gas phase reactions and film composition. Moreover, it induced change in the deposition rate.

Highly reliable ultrathin silicon oxide film formation at low temperature by oxygen radical generated in high-density krypton plasma

This paper focuses attention on electrical properties of silicon oxide films grown by oxygen radical generated in Kr/O/sub 2/ mixed high-density microwave-excited plasma at 400/spl deg/C. They represent high growth rate, low activation energy, high dielectric strength, high charge-to-breakdown, and low interface trap density and bulk charge enough to replace thermally grown silicon oxide.

Electrical properties of bulk silicon dioxide and SiO2/Si interface formed by tetraethylorthosilicate (TEOS)-oxygen plasma enhanced chemical vapor deposition

The electrical properties of bulk silicon dioxide and the SiO2/Si interface formed by TEOS/O2 PECVD were investigated. Additionally, the gas phase in the glow discharge was investigated using OES analysis under various experimental conditions. Changes of TEOS/O2 ratio and the deposition temperature influenced the electrical properties of silicon oxide films. With decreasing TEOS/O2, ratio, the electrical properties of bulk silicon dioxide and the SiO2/Si interface were improved. This is thought to be due to the decrease of carbon impurity in the growing oxide film. At higher deposition temperatures, the oxide films had good electrical properties, which is thought to be due to the change of structure in the oxide film. From C–V analysis for all experimental conditions, the Pb center defects were observed near Ev+0.25eV and Ev+0.73eV in the Si band gap. The magnitude was influenced by process parameters such as the TEOS/O2 ratio and the deposition temperature. From OES analysis, the main emission peaks observed in the glow discharge were from CO, CO2+, CH, and C. With decreasing TEOS/O2 ratio, the emission intensity of CH decreased and that of CO increased.

The effect of rapid thermal annealing on properties of plasma enhanced CVD silicon oxide films

The effect of rapid thermal annealing in oxygen and nitrogen ambients on the properties of silicon oxide films of different stoichiometry was studied. The films were deposited on silicon wafers by plasma enhanced chemical vapour deposition (PECVD) from silane (SiH 4) and nitrous oxide (N 2O) at different N 2O/SiH 4 flow ratios. It was found that rapid thermal annealing significantly affects the thickness of deposited oxides and the total mechanical stress in the film. The density and the refractive index of the film hardly changed. The hydrogen content of the films has been discussed on the basis of Fourier transform infrared transmission spectroscopy, and is related to the changes in the film properties.

Thermal conductivity of SiO 2 films by scanning thermal microscopy

In microelectronics the thermal conductivity of dielectric films such as SiO 2 is of concern because, as dimensions shrink, heat removal from devices becomes a critical problem. A scanning thermal microscope was used to image thermal properties of silicon dioxide films deposited on silicon by plasma enhanced chemical vapor deposition. Thermal conductivity as a function of the layer thickness, ranging 50–1000 nm was measured. To interpret the experimental thermal data, a model has been developed on the basis of previously published heat-transfer concepts. An intrinsic thermal conductivity of 1.31 ± 0.11 W/K/m was calculated independent of the thickness and a thermal resistance of (6.8 ± 0.35) × 10 −7 m 2 K/W was calculated at the interfaces.

Properties of silicon oxide films deposited by plasma-enhanced CVD using organosilicon reactants and mass analysis in plasma

Silicon oxide films were deposited at room temperature on Si substrates by remote-type plasma enhanced chemical vapor deposition using tetramethoxysilane and oxygen. Fourier transform infrared spectroscopy revealed that the carbon contamination in the deposited films are in the state of Si-CH 3. Quantitative analysis by X-ray photoelectron spectroscopy elucidated that the oxygen partial pressure ratio is needed to be <40% in order to synthesize pure silicon oxide films without the carbon contamination. Mass analysis showed that almost reactant organosilicon molecules were fragmented into small gaseous species in the plasma even without oxygen. The origin of the carbon contamination was adsorption of CH 3 radicals onto the film surface. The existence of oxygen molecules in vapor phase resulted in the deposition of carbon-free silicon oxide films.

The Boundary Between Hard- and Soft-Breakdown in Ultrathin Silicon Dioxide Films

ABSTRACTThe dielectric breakdown is an irreversible and transient process, and it is difficult to understand its dynamic characteristics. We notice that the post-breakdown electrical properties of silicon dioxide films may include much information on the dielectric breakdown mechanism. First, the resistance of silicon dioxide films after the dielectric breakdown is statistically investigated, and then this analysis is applied to differentiate the hard- from the soft-breakdown. In particular, we discuss the critical dependence of the boundary between the hard- and softbreakdown on the discharging time constant as well as the discharging energy at the breakdown, concerning the formation of the conductive filament in the insulator silicon dioxide films. It should be noted that the ratio of the soft- to the hard-breakdown changes in terms of the statistical distribution in the case that the growth parameters and the measurement conditions are changed. In partcular, the external inductance effect to modify the discharging time constant in the MOS circuit is discussed. The thickness limitation of the silicon dioxide film in the roadmap is in this transition region, and this fact will be of essential importance in the assessment of the reliability and the process control of silicon device fabrication in sub-5nm silicon dioxide regime.

Effects of oxygen content on properties of silicon oxide films prepared at room temperature by sputtering-type electron cyclotron resonance plasma

We present the study of the effects of gas-phase oxygen fraction on properties of silicon oxide films prepared in a sputtering-type electron cyclotron resonance plasma discharge. Dielectric breakdown characteristics of the films are considerably improved by an increase in oxygen flow rate, FO2, with a constant Ar gas flow rate of 16 sccm. Films prepared at FO2 of more than 6 sccm have good dielectric breakdown fields of 9–11 MV/cm, which are comparable with those of high quality thermally grown SiO2. Moreover, the increase of FO2 improved structural properties of the films. Detailed measurements of their composition and microstructure were carried out using ellipsometry, chemical etch rate measurement in a mixture of HF, H2O, and HNO3 (P etch), x-ray photoelectron spectroscopy (XPS), and infrared (IR) spectroscopy techniques. Ellipsometry and XPS measurements indicated that films prepared at FO2 of more than 3 sccm are stoichiometric. Dependence of the IR spectra and P etch rate on FO2 of more than 3 sccm indicated that distribution of Si–O–Si bond angle and Si–O bond strain in the films decreases with an increase of FO2. Based on the behavior of the Si–O–Si bond angle and refractive index of the films, we discuss the improvements in structural properties in terms of growth kinetics.

Electron cyclotron resonance (ECR) plasma-enhanced chemical vapour deposition of silicon dioxide on strained-SiGe films using tetraethylorthosilicate

Silicon dioxide films on strained Si1−x Ge x have been deposited by electron cyclotron resonance (ECR) plasma-enhanced chemical vapour deposition technique using tetraethylorthosilicate (TEOS) at room temperature. The deposition rate as a function of time and substrate temperature has been studied. MOS capacitors fabricated using deposited oxides have been used to characterize the electrical properties of silicon dioxide films. Deposited oxide film shows its suitability for microelectronic applications.

Elastic properties of silicon dioxide films deposited by chemical vapour deposition from tetraethylorthosilicate

Dielectric silicate glass films have been obtained from tetraethylorthosilicate using both low-pressure chemical vapour deposition and plasma-enhanced chemical vapour deposition. The elastic properties of these films, which are deposited on (100)-Si wafers, have been studied by means of the Brillouin light scattering technique. The phase velocity of both the surface Rayleigh wave and the longitudinal wave in the film material have been measured and the two independent elastic constants c 11 and c 44 evaluated. This permitted us to derive the values of Young's modulus and Poisson's ratio which are useful quantities for the modelling of the elastic properties of multilevel structures used in electronics. Moreover, the substrate curvature method has been exploited in the case of the PECVD film, to study the evolution of the stress during subsequent thermal cycles. The values of the thermal expansion coefficient and of the water diffusion coefficient have thus been determined.

Electrical properties of PECVD oxide films deposited at room temperature

The authors discuss the electrical properties of silicon oxide films deposited at room temperature by PECVD, using disilane as the silicon source. In experiments, the interface trap density of the films with post-metallisation anneal showed a minimum value of 6.33 × 1011 cm-2eV-1, which is 36.6% lower than that of the as- deposited films. The authors also show that the films annealed in hydrogen-containing ambient reduced the early breakdown failures, resulting in an overall improvement of film integrity.

Mechanisms of Silicon Dioxide Deposition from the Low Pressure Chemical Vapor Deposition of Diethylsilane/Oxygen Mixtures

Studies of the gas‐phase products, silicon dioxide film properties, and kinetics of the diethylsilane/oxygen reaction under low pressure chemical vapor deposition (LPCVD), conditions in both packed and unpacked stirred flow reactors are reported. Effects of flow rate, reactant composition, pressure, and various additives (e.g., ethene, helium, toluene, methylchloride, and various peroxides) on the reaction products, product yields, and reaction rates confirm the free radical nature of the reaction and provide mechanistic interpretations for the “cutoff” and “start‐up” problems sometimes encountered in the film deposition process. Additions of free radical source molecules promote the reaction. Thus process temperatures substantially lower than normal (i.e., ) can be used in the LPCVD process without effecting either film quality or film deposition rate. This process temperature lowering was a main study objective. Best results, as judged by film quality and uniformity, were achieved by matching the LPCVD reactor residence time of the reaction mixture to the decomposition lifetime of the promoter. Effective process temperatures were 315°C with added, 270°C with added , and 250°C with added .

Effect of power on interface and electrical properties of SiO2 films produced by plasma-enhanced chemical-vapor deposition

The effect of power on the electrical and interface properties of silicon dioxide films produced by direct plasma-enhanced chemical-vapor deposition, using nitrous oxide and silane with high helium dilution, has been investigated. Auger depth profiling measurements indicate that while the bulk of the films have no measurable impurities, the interface region contains about 1.6×1015 atoms/cm2 of nitrogen. In contrast to thermal oxides, there is no thick interface layer with a large intrinsic compressive stress. The interface-state densities of the films obtained from capacitance-voltage measurements on metal-oxide-semiconductor diodes increase with increasing plasma power, but these can be removed to some extent by high-temperature annealing at temperatures in the range 800–950 °C. The flatband voltage is relatively insensitive to plasma power. Thermal oxide samples have been subjected to the plasma processes and these also show evidence of plasma damage. A thin layer produced at the interface by a separate plasma oxynitridation process is shown to be incapable of protecting the Si/SiO2 interface from the plasma damage produced by subsequent high-power plasma deposition processes. The nature of the interface states is discussed.