共查询到20条相似文献,搜索用时 31 毫秒
1.
Using the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique, SiC films were fabricated from the gas mixture of He, H2, SiH4 and CH4 on silicon substrates. High-power-density condition was adopted to sufficiently activate the reactive gas molecules in the plasma. The structure, composition and crystallinity of the films were investigated as functions of the H2 concentration in the gas mixture and substrate temperature. It was shown that increase in H2 concentration in the plasma atmosphere reduced the growth temperature of polycrystalline SiC film. As a result, polycrystalline 3C-SiC film of which grain size was of the order of 10 nm could be grown at a substrate temperature of 820 K with a deposition rate of approximately 6.7 nm/s. It was suggested that atomic hydrogen generated with addition of H2 in the gas mixture considerably affects not only the reaction process at the film-growing surface but also the form of precursors in the atmospheric pressure plasma. The results indicated the possibility of realizing the columnar growth of large 3C-SiC grains on Si substrate when the H2 concentration and the VHF power were simultaneously increased in the AP-PCVD process. 相似文献
2.
We investigated an influence of gas pressure on low-temperature preparation of nanocrystalline cubic silicon carbide (nc-3C-SiC) films by hot-wire chemical vapour deposition (HW-CVD) using SiH4/CH4/H2 system. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectra revealed that the films prepared below 1.5 Torr were Si-nanocrystallite-embedded hydrogenated amorphous SiC. On the other hand, nc-3C-SiC films were successfully prepared at gas pressure above 2 Torr. The high gas pressure plays two important roles in low-temperature preparation of nc-3C-SiC films: (1) leading to sufficient decomposition of CH4 molecules through a gas phase reaction and an increase in the incorporation of carbon atoms into film and (2) promoting a creation of H radicals on the heated filament, allowing the sufficient coverage of growing film surface and a selective etching of amorphous network structure and/or crystalline-Si phase. It was found that total gas pressure is a key parameter for low-temperature preparation of nc-3C-SiC films. 相似文献
3.
《Thin solid films》1999,337(1-2):18-22
The control of grain orientation in polycrystalline silicon thin films on glass substrates by low-temperature techniques was investigated. Either (220) or (400) preferential grain orientation could be attained by control of source gas ratio over substrate temperatures between 250°C and 360°C. A remote type plasma chemical vapor deposition system was used with source gas mixtures of SiF4, H2 and Ar. The (220) preferential films were obtained with Ar/H2/SiF4 gas flow rates of 60/15/30 sccm (respectively), while the (400) preferential oriented films were obtained at higher SiF4/H2 ratios (SiF4/H2=90/10 sccm). At the higher SiF4/H2 ratio during the crystal nucleation stage, either randomly oriented or (400) grains formed followed by the highly preferred deposition of (400) oriented crystallites. Raman scattering and ellipsometry spectra indicated that the (400) oriented films had a very smooth surface. 相似文献
4.
Hirofumi Takikawa Nobuhide Miyakawa Shinji Minamisawa Tateki Sakakibara 《Thin solid films》2004,457(1):143-150
Diamond-like carbon (DLC) films were prepared on rubber substrates using T-shape filtered-arc-deposition (T-FAD), which effectively removes the macrodroplets emitted from the graphite cathode spot from the processing plasma. In the present study, the influence of ambient gas (no gas, Ar, H2, C2H2, C2H4, CH4) was investigated. The DLC films adhered well to the rubber substrate. When the substrate was stretched, the small DLC islands were separated and clefs were opened. The deposition rate on rubber was approximately twice higher than that on a Si substrate. When hydrocarbon gas was introduced as an ambient gas, the deposition rate became higher than that for no gas and H2 gas. In the cases of C2H4 and CH4 gases, the DLC film was considered to contain a considerable amount of hydrogen. When C2H2 gas was used, the highest deposition rate with less surface roughness was achieved. 相似文献
5.
Silicon carbide (SiC) thin films were prepared by hot-wire chemical vapor deposition in a CH4 gas flow rate of 1 sccm, and the influence of the gas flow rates of SiH4 and H2 gases on the film structure and properties were investigated. In the case of a H2 gas flow rate below 100 sccm, the SiC:H films obtained in SiH4 gas flow rates of 3 and 4 sccm were amorphous. On the other hand, when the H2 gas flow rate was above 150 sccm, SiH4 gas flow rates of 4 and 3 sccm resulted in a Si-crystallite-embedded amorphous SiC:H film and a nanocrystalline cubic SiC film, respectively. It was found that gas flow rates were important parameters for controlling film structure. 相似文献
6.
Yasuaki Komae Maki Suemitsu Tetsuo Endoh Yuzuru Narita Tadashi Akahane 《Thin solid films》2009,517(12):3528-4431
Gallium nitride (GaN) films and Aluminium nitride (AlN) layers were deposited on SiC/Si (111) substrates by an alternating source gas supply or an intermittent supply of a source gas such as ammonia (NH3), trimethylgallium (TMG) or trimethylaluminum (TMA) in a hot-mesh chemical vapor deposition (CVD) apparatus. The AlN layer was deposited as a buffer layer using NH3 and TMA on a SiC layer grown by carbonization on Si substrates using propane (C3H8). GaN films were grown on an AlN layer by a reaction between NHx radicals generated on a ruthenium (Ru) coated tungsten (W)-mesh and TMG molecules. An alternating source gas supply or an intermittent supply of one of the source gases during the film growth are expected to be effective for the suppression of gas phase reactions and for the enhancement of precursor migration on the substrate surface. By the intermittent supply of alkylmetal gas only during the growth of the AlN layer, the defect generation in the GaN films was reduced. GaN film growth by intermittent supply on an AlN buffer layer, however, did not lead to the improvement of the film quality. 相似文献
7.
NiSix films were deposited using chemical vapor deposition (CVD) with a Ni(PF3)4 and Si3H8/H2 gas system. The step coverage quality of deposited NiSix was investigated using a horizontal type of hot-wall low pressure CVD reactor, which maintained a constant temperature throughout the deposition area. The step coverage quality improved as a function of the position of the gas flow direction, where PF3 gas from decomposition of Ni(PF3)4 increased. By injecting PF3 gas into the Ni(PF3)4 and Si3H8/H2 gas system, the step coverage quality markedly improved. This improvement in step coverage quality naturally occurred when PF3 gas was present, indicating a strong relationship. The Si/Ni deposit ratio at 250 °C is larger than at 180 °C. It caused a decreasing relative deposition rate of Ni to Si. PF3 molecules appear to be adsorbed on the surface of the deposited film and interfere with faster deposition of active Ni deposition species. 相似文献
8.
Ge1−xCx thin film was prepared by plasma-enhanced chemical vapor deposition (PECVD) using GeH4 and CH4 as precursors and its mechanical and environmental properties were investigated. The samples were measured by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectrum, FT-IR spectrometer, WS-92 testing apparatus of adhesion and FY-03E testing apparatus of salt and fog. The results show that the infrared refractive index of Ge1−xCx thin film varies from 2 to 4 with different x values. The adhesion increases with increasing gas flow ratio of GeH4/CH4 and decreases with increasing film thickness. The nanoindentation hardness number decreases with increasing germanium content. Three series films exhibit the best anti-corrosion property when the RF power is about 80 W, or substrate temperature is about 150 °C, or DC bias is about −100 V. Furthermore, increasing the gas flow ratio of GeH4/CH4 improves the anti-corrosion property of these films. 相似文献
9.
We have deposited hydrogenated microcrystalline silicon films by standard rf glow discharge plasma CVD technique using a mixture of SiF4, Ar and H2 at low substrate temperatures. Although fully crystalline from the beginning of the growth, our films show a significant variation in the ratio of large (LG) and small grain (SG) with further growth, for any H2 dilution case, though the trend changes for each case. The mean sizes of the LG and SG do not vary much with growth, but a marked variation occurs in the size of the conglomerate grains, as shown by atomic force microscopy (AFM) studies. Notably, a change in the H2 dilution is found to affect not only the film microstructure, but also the crystalline orientation. We have shown the lateral and longitudinal growth of conglomerate grains to be highly dependent on the crystalline orientation. In studying the effect of film growth on film roughness, we have observed a linear correlation between the rms roughness as measured by AFM and the top surface layer as measured by spectroscopic ellipsometry. We have also succeeded in elucidating the growth mechanisms involved, apropos of surface roughness findings. 相似文献
10.
《Thin solid films》1999,337(1-2):7-11
Polycrystalline silicon films have been prepared at low temperature on glass substrate from fluorinated precursors by PECVD technique varying the hydrogen dilution and gas flow rate. Undoped film with dark-conductivity 1.05×10−2 S cm−1 has been obtained. For n-type poly-Si film the highest conductivity achieved is 2.8 S cm−1. Grain size observed from SEM varies from 4 to 6 μm for undoped and 2 to 3 μm for phosphorous doped films. The main crystalline peak is 〈111〉 whereas the crystallite size calculated from XRD is 350 Å. The optical absorptions and hydrogen contents in the films deposited under different conditions have been studied. Growth kinetics are dominated by the precursors SiFnHm (m+n≤3) and concentrations of F and H on the growth surface. 相似文献
11.
This study presents a systematic investigation of the microstructure dependence of liquid phase deposition (LPD) of SiO2 films on solution parameters and deposition temperature. The corresponding deposition rate and film roughness were also evaluated under various deposition conditions. Smooth and sufficiently dense SiO2 films, which are the prerequisite for reliable low-k dielectric applications, were deposited on both silicon and fluorine-doped tin oxide coated glass substrates from supersaturated hydrofluorosilicic acid (H2SiF6) solution with the addition of boric acid (H3BO3). It is shown that H2SiF6 acid controls the surface morphology and grain structure through surface reaction while H3BO3 acid prompts bulk precipitation in solution. For the 208-nm thick SiO2 film, the breakdown field exceeded 1.9 MV/cm and the leakage current density was on the order of 10− 9 A/cm2 at 4 V, indicating excellent insulating properties of LPD SiO2 films. The strong presence of Si-O-Si and some Si-F with little Si-OH bond as shown in FT-IR spectra indicate that the LPD SiO2 films have mostly a silica network with some fluorine (F) content. F-doping was self-incorporated into the silica films from the H2SiF6 solution during deposition process. 相似文献
12.
The n-type doped silicon thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) technique at high and low H2 dilutions. High H2 dilution resulted in n+ nanocrystalline silicon films (n+ nc-Si:H) with the lower resistivity (ρ ∼0.7 Ω cm) compared to that of doped amorphous silicon films (∼900 Ω cm) grown at low H2 dilution. The change of the lateral ρ of n+ nc-Si:H films was measured by reducing the film thickness via gradual reactive ion etching. The ρ values rise below a critical film thickness, indicating the presence of the disordered and less conductive incubation layer. The 45 nm thick n+ nc-Si:H films were deposited in the nc-Si:H thin film transistor (TFT) at different RF powers, and the optimum RF power for the lowest resistivity (∼92 Ω cm) and incubation layer was determined. On the other hand, several deposition parameters of PECVD grown amorphous silicon nitride (a-SiNx:H) thin films were changed to optimize low leakage current through the TFT gate dielectric. Increase in NH3/SiH4 gas flow ratio was found to improve the insulating property and to change the optical/structural characteristics of a-SiNx:H film. Having lowest leakage currents, two a-SiNx:H films with NH3/SiH4 ratios of ∼19 and ∼28 were used as a gate dielectric in nc-Si:H TFTs. The TFT deposited with the NH3/SiH4∼19 ratio showed higher device performance than the TFT containing a-SiNx:H with the NH3/SiH4∼28 ratio. This was correlated with the N−H/Si−H bond concentration ratio optimized for the TFT application. 相似文献
13.
Jong Seong BaeByung Kee Moon Byung Chun ChoiJung Hyun Jeong Soung Soo YiIll Won Kim Jeong Sik Lee 《Thin solid films》2003,424(2):291-295
ZnGa2O4 thin film phosphors have been deposited using a pulsed laser deposition technique on Si (1 0 0) and Al2O3 (0 0 0 1) substrates at a substrate temperature of 550 °C with various oxygen pressures 100, 200 and 300 mTorr, and various substrate temperatures of 450, 550 and 650 °C with a fixed oxygen pressure of 100 mTorr. The films grown under different deposition conditions have been characterized using microstructural and luminescent measurements. Under the different substrate temperatures, ZnGa2O4 thin films show the different crystallinity and luminescent intensity. The crystallinity and photoluminescence (PL) of the ZnGa2O4 films are highly dependent on the deposition conditions, in particular, oxygen pressure, substrate temperature, a kind of substrates. The luminescent spectra show a broad band extending from 350 to 600 nm peaking at 460 nm. The PL brightness data obtained from the ZnGa2O4 films grown under optimized conditions have indicated that the sapphire is one of the most promised substrates for the growth of high quality ZnGa2O4 thin film phosphor. 相似文献
14.
We investigated the effects of nanostructures of obliquely co-sputter-deposited thin films in terms of catalytic properties using pulses of reactant molecules as probes. Pt-Al2O3 thin films were fabricated on a Si substrate by simultaneous oblique deposition. The films had columnar structures that grew perpendicular to the substrate. We observed the behavior of NO reduction by H2 with a specially designed apparatus employing pulse valves for the injection of reactant molecules onto the thin film surface and a time-of-flight mass spectrometer to measure plural products. The obliquely co-deposited films, consisting of columnar nanostructures, showed higher NO reduction activity over a wide range of temperatures than the normally co-deposited films, consisting of uniform structures. The yield of N2 exceeded that of NH3 and N2O for both structures in the high temperature range, whereas the yield of N2O was more significant for the structures with columns than those without columns at low temperatures. Subtle change of the nanometer-scale structures with the deposition angle was clearly discriminated from the viewpoint of transient catalytic activity. 相似文献
15.
《Thin solid films》1999,337(1-2):59-62
A high degree of crystallinity is obtained in nc-Si:H films deposited by r.f. PECVD, produced from SiF4-H2-He mixtures. The amorphous-to-nanocrystalline transition is favored because of the presence of F atoms, which preferentially etch the amorphous phase. The addition of He to the SiF4-H2 gas mixture gives an increase of F and H atoms in the plasma, thus inducing higher crystallinity. A further improvement in the nc-Si:H film structure and properties is obtained by adjusting the r.f. power and the deposition temperature. Under optimized plasma conditions, substrate temperatures as low as 120°C can be reached for the deposition of nc-Si:H having 100% of crystallinity. 相似文献
16.
Ni-silicide film was deposited at a low temperature of 160 °C by CVD using a Ni(PF3)4/Si3H8 gas system. Injecting Si3H8 during the Ni deposition does not affect the deposition rate, but the step-coverage quality deteriorates at high growth temperatures. At high growth temperatures, the Ni/Si ratio of the film deposited on the sidewall varies as the distance from the open area increases. High step-coverage quality and a constant Ni/Si ratio independent of the location of the deposition are strongly required to fabricate a three-dimensional device. These requirements were achieved with this CVD by depositing the Ni-silicide film below 180 °C. 相似文献
17.
Sophie Gledhill Rebecca AllisonNicholas Allsop Yanpeng FuElisavet Kanaki Rodrigo Sáez-AraozMartha Lux-Steiner Christian-Herbert Fischer 《Thin solid films》2011,519(19):6413-6419
The spray Ion Layer Gas Reaction (ILGAR) is a well-established, patented and commercial process used primarily to deposit In2S3 as buffer layers in thin film solar cells. In this paper we investigate the growth mechanism of the spray In2S3 ILGAR process by characterising the intermediate growth stages of films, following the growth mechanism with a quartz crystal microbalance and tracking the gaseous side-and-intermediate products during film growth, using a mass spectrometer. A basic growth mechanism model is then proposed based on an aerosol assisted chemical vapour deposition of an In(Ox,Cly,(OH)z) film, as the first stage process, followed by the conversion of the intermediate film using H2S gas to In2S3. 相似文献
18.
We propose a new high-rate reactive sputter-deposition method with two sputtering sources for fabricating TiO2 films. One source operates in a metal mode sputtering condition and supplies titanium atoms to the substrate. The other source operates in oxide mode and works as an oxygen radical source for supplying oxygen radicals to the substrate surface for promoting oxidization of titanium atoms. Each sputtering source is separated with a mesh grid from the deposition chamber, and Ar and oxygen gas are introduced separately through the titanium supply and oxygen radical sources, respectively. By using this reactive sputtering system, a deposition rate above 80 nm/min can be obtained for the deposition of TiO2 films with rutile structure. 相似文献
19.
Nanocrystalline materials are of high interest, because mechanical and physical properties of such materials are different from those or coarse-grained type. Continuous and smooth nanocrystalline diamond (NCD) thin films were successfully grown on mirror polished silicon substrates, using double bias plasma-enhanced hot filament chemical vapour deposition technique. A gas mixture of Ar:CH4:H2 and CH4:H2 was used as the precursor gas. The effect of the gas composition, flow rate and substrate bias during deposition on diamond crystallite size was investigated. Changing the growth parameters facilitates control of grain size of polycrystalline diamond thin films from microcrystalline to nanocrystalline. The structure of fine-grained NCD films has been studied with scanning electron microscopy and Raman spectroscopy. 相似文献
20.
We investigated the growth characteristics of the nanocrystalline diamond films using CCl4/H2 as gas sources in a hot-filament chemical vapor deposition (CVD) reactor. Successful growth of nanocrystalline diamond at typical growth condition of 1.5-2.5% CCl4 and 550-730 °C substrate temperature has been demonstrated. Glancing angle X-ray diffraction (XRD) clearly indicated the formation of diamond in the films. Typical root-mean-square surface roughness of 10-15 nm and an optimal root-mean-square surface roughness of 6 nm have been achieved. Transmission electron microscopy (TEM) analyses indicated that nanocrystalline diamond film with an average grain size in the range of 10-20 nm was deposited from 2.5% CCl4/H2 at 610 °C. Effects of different source gas composition and substrate temperature on the grain nucleation and grain growth processes, whereby the grain size of the nanocrystalline film could be controlled, were discussed. 相似文献