Plasma-enhanced reactively evaporated deposition of SiO2 films (original) (raw)
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Structural properties of SiO2 films prepared by plasma-enhanced chemical vapor deposition
Materials Science in Semiconductor Processing, 2001
SiO 2 thin films have been prepared by plasma-enhanced chemical vapor deposition from SiH 4 and N 2 O precursors by using different values of the N 2 O/SiH 4 flow ratio (g). Rutherford backscattering spectrometry has been employed to obtain the O/Si atomic ratio of the films. Infrared spectroscopy has demonstrated that oxides having the same O/Si atomic ratio are characterized by a different structure. Indeed, from the analysis of the Si-O-Si stretching peaks, we have found that the peak frequency and full-width at half-maximum (FWHM) are dependent on g. Peak position and FWHM have been used to calculate the bond angle distribution of the films. The results have demonstrated the occurrence of a Si-O-Si bond angle relaxation phenomenon in films deposited by using a larger excess of N 2 O. #
Low-temperature plasma enhanced chemical vapor deposition of SiO2
Silicon dioxide ~SiO2! films, with qualities approaching to those of thermal oxide, were deposited at 40 °C in a helical resonator plasma reactor from tetraethylorthosilicate ~TEOS! and oxygen discharge. The films were characterized using transmission infrared spectroscopy, variable angle spectroscopic ellisometry, and wet etch rate measurements. It was found that the TEOS/O2 ratio, R, in plasma enhanced chemical vapor deposition of SiO2 is as important a parameter as the substrate temperature. Using low TEOS/O2 ratio ~R,1:20!, high quality SiO2 films could be deposited by PECVD at room temperature. At high TEOS/O2 ratio, particularly at low temperature, ethoxy ligands of the TEOS molecule are incorporated into the film disrupting the connectedness of the SiO4 tetrahedra resulting in porous, low density films with high OH content.
In this paper we report on synthesis of thin films of silicon dioxide (SiO2) using conventional plasma enhanced chemical vapor deposition (PE-CVD) from pure silane (SiH4) and oxygen (O2), gas mixture at low RF power (30 Watt) and at moderate substrate temperature (250 qC). We have systematically investigated the material properties of these films as a function of oxygen partial pressure in view of their use in MOS devices. The formation of SiO2 thin films is confirmed by Fourier transform infrared (FTIR) spectroscopy. The thickness and refractive indices of the films measured by ellipsometry. C-V measurement shows that the electrical properties are directly related to process parameters and Si/SiO2 interface. The MOS structures were also fabricated from optimized SiO2 layer to study C-V measurement and to estimate interface, oxide and effective border traps density.
Investigation of low temperature SiO2 plasma enhanced chemical vapor deposition
Low temperature ~,270 °C! plasma enhanced chemical vapor deposition ~PECVD! of SiO2 thin films using tetraethylorthosilicate ~TEOS! and O2 plasma was investigated. Depositions were carried out in a PECVD reactor with a helical resonator discharge source. Transmission infrared spectroscopy, spectroscopic ellipsometry, and wet etch rate measurements were used to characterize the deposited films as a function of rf power, gas composition, and substrate temperature. Most pronounced effects were observed when the substrate temperature and TEOS:O2 flow ratio R were varied. Good quality SiO2 films can be obtained at high temperature and/or low R. For R.0.1, while the deposition rate was weakly dependent on temperature between 260 and 100 °C, it increased almost by a factor of 2 between 100 and 45 °C. This is also accompanied by drastic changes in film properties such as refractive index, increase in OH and –OC2H5 content, and decrease in film density. Studies using in situ attenuated total reflection Fourier transform infrared ATR FTIR spectroscopy indicated that stable good quality SiO2 films without any SiOH at higher temperature ~250 °C and with very little SiOH at room temperature could be deposited using very low R. Based on the understanding provided by ATR FTIR, films with properties approaching to those of thermal oxide have been deposited at room temperature.
Deposition of High-Quality SiO2 Insulating Films at Low Temperatures by means of Remote PECVD
IEEE Transactions on Electron Devices - IEEE TRANS ELECTRON DEVICES, 2008
Silicon dioxide films were deposited by means of remote inductively coupled plasma enhanced chemical vapor deposition (ICPECVD) in Ar-N2O-SiH4 plasma at 150 °C and pressures between 1 and 6 Pa. The gas phase contained 0.08% of SiH4 and 18% of N2O. We observed that, at a total pressure of 1 Pa, the oxide films were formed with a density equal to that of thermally grown oxide. The films had a low oxide charge. Deposition at higher pressures resulted in the formation of oxides having a lower density than the film deposited at 1 Pa, and a higher oxide charge. We measured a strong dependence of the oxide charge on the film thickness. The films deposited at 1 Pa further exhibited leakage currents at an electric field strength of 6.5 MV/cm which were comparable to the leakage currents known for thermally grown (1000°C) oxides. The film deposited at 2 Pa also exhibited a low leakage current, but the current increase was observed at lower electric fields compared to the 1 Pa film. The films ...
Journal of Applied Physics, 1983
Plasma enhanced chemically-vapor-deposited silicon-rich oxides (200 Å and 500 Å in thickness) of various excess silicon content were deposited onto thermal silicon dioxide (SiO2) layers (103, 207, and 530 Å in thickness) grown on a p-type silicon (Si) substrate. The dielectric constant, electron injection efficiency, current-voltage (I-V) reproducibility, and breakdown property of these composite structures were examined. The dielectric constants of Si-rich oxide were observed to increase with Si content from 3.8 for films deposited at a gas phase ratio (R0) of the concentration of nitrous oxide (N2O) to silane (SiH4) of 150 to ∼10 for films deposited with R0=0. The Si-rich oxides with R0≤5 were found to work as electron injectors. The average oxide field needed to induce a current of 4.8×10−7 A/cm2 through the SiO2 (530 Å in thickness) decreased about 40% in magnitude by adding a Si-rich oxide layer with the optimized R0(=1) compared to that of a control sample which had no Si-rich...
Physica Status Solidi (c), 2007
SiO 2 films by atmospheric pressure chemical vapor deposition (APCVD) process, using tetraethoxysilane (TEOS) and ozone (O 3 ) as reactant were obtained. The films were deposited on silicon substrates at various temperatures 125, 150, 175, 200, 225 and 250 °C Fourier transforms infrared (FTIR) spectroscopy was used to characterize the SiO 2 films. Absorbance spectrums show the vibration modes corresponding to SiO 2 films. Additional absorption bands due to residual groups were also observed, but they were found to be dependent on the deposition temperature. The observed current flowing through the oxide could be related to these residual groups, mainly to hydroxyl groups.
Characterization of SiO2 films deposited at low temperature by means of remote ICPECVD
2007
Silicon dioxide films were deposited by means of remote inductively coupled plasma enhanced chemical vapor deposition (ICPECVD) in Ar-N 2 O-SiH 4 plasma at 150°C and pressures between 1 and 6 Pa. Chemical modeling of our plasma indicated an increased fraction of SiH 3 radicals at 6 Pa (compared to SiH 2 , SiH, and Si species), while at 1 Pa their relative contribution on film growth should be much smaller. Layer growth from SiH 3 radicals would result in better dielectric quality.