Function Of Substrate Temperature Research Articles

Removal of SOC Hard Mask for Patterning of Work Function Metal by Thermally Activated Ozone Gas

Thermally activated ozone gas (TAO) was demonstrated as an alternative technology to conventional spin-on carbon (SOC) stripping. The SOC stripping rate with ozone gas was found to be a function of substrate temperature and actual ozone amount calculated from the ozone flow rate and concentration. Furthermore, work function metal (WFM) stripping rate showed a high selectivity to SOC films, and the amount of oxidation TiN, which is a WFM metal, was also equivalent to conventional technology of SOC stripping. This TAO gas process can be used in clean tools, making it a promising integrated solution for SOC stripping followed by post clean.

Optimization of structural and optical properties of sputter deposited TiO2 thin films by controlling deposition parameters

Titanium oxide (TiO2) thin films have been deposited onto highly cleaned soda lime glass substrates by DC magnetron reactive sputtering system. The Ti target with purity 99.99% is sputtered by argon gas in the sputtering chamber. Oxygen gas with purity 99.99% is introduced during the deposition process into the sputtering chamber as reactive gas for the synthesis of titanium oxide. Structural and optical properties of TiO2 thin films have been characterized by X-ray diffraction (XRD), Raman spectroscopy and UV-Vis. spectroscopy. The effect of substrate temperature and sputtering power on the optical properties of TiO2 thin films has been studied. The XRD and Raman spectroscopy of as-deposited films are used to study the structural properties of TiO2 as a function of substrate temperature and sputtered power. The structural studies show the crystalline nature of TiO2 thin films. The narrowing of energy band gap of sputtered deposited TiO2thin films was studied using UV-Vis. spectroscopy.

Effect of substrate temperature and preferred orientation on the tribological properties of Tantalum nitride coatings

Abstract Tantalum nitride (TaN) coatings have been deposited on Stainless steel (SS 316L) substrates by magnetron sputtering technique. The structural, morphological and tribological characteristics as a function of substrate temperature (Ts) have been studied using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Linear reciprocating tribometer. XRD analysis revealed that the coatings showed cubic phase and no secondary phase has been formed in coatings during deposition. XRD also revealed that the preferred orientation of coatings changes with change in Ts. Crystallite size was increased with increasing Ts from 200 °C−400 °C. The tribological properties of TaN coatings with respect to Ts and preferred orientation were studied. The results revealed that there is a significant impact of Ts and preferred orientation on tribology properties. The coating deposited at 400 °C with (2 2 0) preferred orientation shows lower coefficient of friction with enhanced wear resistance compared to the other two coatings deposited at 200 °C and 300 °C.

Investigation on dispersion parameters of Molybdenum Oxide thin films via Wemple–DiDomenico (WDD) single oscillator model

In this paper, the dispersion parameters of Molybdenum Oxide thin films viz: oscillator energy, dispersion energy, transition moments, static refractive index, oscillator strength, and oscillator wavelength are estimated via Wemple–DiDomenico (WDD) single oscillator model. The crystal structural, surface morphological, and optical transmission properties of Molybdenum Oxide thin films are also investigated so as to extract vital in-put parameters for WDD model. The X-ray Diffraction and Fourier Transform of Infrared analysis confirm that the film fabricated at substrate temperature ~ 300 °C under goes a successful dual phase transformation from amorphous to α- and β-MoO3 crystalline phase. Static refractive indices of the films are found to be vary from ~ 1.84 to 2.04 with the increase of substrate temperature during the thin film growth process via thermal evaporation technique. Moreover, the optical constants viz: film density, porosity, absorption coefficient, optical band gap, Urbach energy, steepness parameter, and strength of electron–phonon interaction are also studied as a function of substrate temperature. This is to establish a correlation between optical constants and dispersion parameters in the present paper.

Optical and dispersion parameters of co-evaporated SnS0.7Se0.3 thin films

Tin sulfoselenide (SnS 1-x Se x ) is a novel ternary semiconductor that belongs to the IV – VI group of compounds. It possesses the properties of both SnS and SnSe, which are proved as good absorber materials for solar cell fabrication. In the present work, SnS 0.7 Se 0.3 thin films were deposited by vacuum co-evaporation technique at four different substrate temperatures ( T s ), 200 °C, 250 °C, 300 °C and 350 °C. The optical properties of as-deposited SnS 0.7 Se 0.3 films were analyzed using optical measurements. From the optical transmittance and reflectance data, the band gap energy of the layers was determined that varied in the range, 1.59–1.46 eV. The other optical parameters such as skin depth, refractive index, extinction coefficient, optical conductivity and dielectric constant of SnS 0.7 Se 0.3 layers were determined and discussed as a function of substrate temperature. Moreover, the dispersion parameters of the layers were also evaluated using Wemple – DiDomenico (WDD) single oscillator model. The dispersion energy ( E d ) and oscillator energy ( Ε o ) of the films were evaluated and varied in the range, 2.19–2.38 eV and 7.55–9.52 eV respectively. Moreover, the optical dispersion moments ( M −1 and M −3 ) were also calculated that were varied from 0.25 to 0.29 and from 2.76 × 10 -3 to 5.08 × 10 -3 respectively.

Crack-free fabrication of Prussian blue-based blending film for the dramatic enhancement of dual electrochromic device

We introduce a method based on particle-printing technology to facilitate the fabrication of crack-free dual electrochromic devices (ECDs). A film prepared by blending Prussian blue (PB) with antimony tin oxide (ATO) powders had a dense structure free of surface cracks and was suitable as both anode and ion storage layers. We investigated the deposition conditions as a function of substrate temperature at room temperature, 80 °C, and 150 °C. The PB/ATO blending film formed at 150 °C had a uniform surface and high crystallinity; this was the optimal substrate temperature. At 150 °C, the as-fabricated dual ECD had an improved diffusion coefficient of 8.70 × 10−9 cm2/S due to the presence of the PB/ATO blending film. Moreover, there was over 4-fold improvement in the transmittance change at 800 nm compared with that of the WO3 film only with no anodic layer. The better ECD properties were attributed to improved ion mobility and ion storage capacity. Therefore, this blending film was successfully fabricated on the substrate without any cracks using facile particle printing technology to be served as both anodic and ion storage layer.

Epitaxial to axiotaxial texture evolution in endotaxial MnP films grown on GaP (100)

Epitaxial to axiotaxial texture transition as a function of substrate temperature is reported in polycrystalline MnP films, which were grown on GaP (100) substrates using metal organic vapor phase epitaxy. At low growth temperatures, the texture consists of a limited number of epitaxial orientations, which have a common alignment (axiotaxy axis). The number of epitaxial orientations increases at higher growth temperatures, while keeping the same axiotaxy axes, such that only axiotaxial texture is observed at growth temperatures above 700 °C. An estimate of the strain values on the axiotaxy axes at the MnP/GaP interface is provided, assuming a periodic interface, which would favor strain minimization as the main reason for the preservation of such a texture. Since MnP grains grow endotaxially on GaP, this texture transition may be a consequence of MnP/GaP interface reconstruction at different growth temperatures.

Substrate Temperature Dependent Physical Properties of Spray Deposited Antimony-Doped SnO2 Thin Films

Antimony doped tin oxide (ATO) thin film has been widely explored as an alternative transparent conducting oxide (TCO) electrode. The ATO thin films are not yet commercialized due to issues in reproducibility and stability of its transparent conducting properties. In this work, properties of spray deposited ATO thin films are explored as a function of substrate temperature. The deposited ATO thin films are investigated using ultraviolet-visible spectrometer, Hall Effect, and temperature-dependent four probe methods. The film deposited at 450°C was found to possess relatively higher transmittance of 89 % with a wide bandgap of 3.81 eV. Furthermore, it also showed good electrical properties such as high carrier concentration (3.12 × 1020 cm−3), high mobility (25.1 cm2/Vs), low sheet resistance (24.9 Ω/□), and an excellent figure of merit value (1.25 × 10−2 Ω−1). The obtained results are correlated with substrate temperature. The activation energies of the ATO thin films are estimated using Arrhenius plot from the temperature-dependent electrical measurement to elucidate the conduction mechanism. The ATO films were also annealed at various temperature to study the stability of the sheet resistance. The results obtained imply the optimized ATO thin films to be a potential alternative TCO candidate.

Solidification of liquid metal drops during impact

Hot liquid metal drops impacting onto a cold substrate solidify during their subsequent spreading. Here we experimentally study the influence of solidification on the outcome of an impact event. Liquid tin drops are impacted onto sapphire substrates of varying temperature. The impact is visualised both from the side and from below, which provides a unique view on the solidification process. During spreading an intriguing pattern of radial ligaments rapidly solidifies from the centre of the drop. This pattern determines the late-time morphology of the splat. A quantitative analysis of the drop spreading and ligament formation is supported by scaling arguments. Finally, a phase diagram for drop bouncing, deposition and splashing as a function of substrate temperature and impact velocity is provided.

Microstructural, optical and electrical properties of CdS thin films grown by spray pyrolysis technique as a function of substrate temperature

In this research, nanocrystalline cadmium sulfide thin films were produced by the spray pyrolysis technique on glass substrates. The effects of substrate temperature in the range 400–550 °C on the structural, morphological, optical, and electrical properties of the thin films were investigated. The thin films have been characterized by investigating their X-ray diffraction, field emission scanning electron microscope (FE-SEM), and optical absorption (UV–Vis) measurements. X-ray analysis revealed that thin films were a polycrystalline structure with the hexagonal phase in all cases and by increasing in substrate temperature, crystallite size decreases, and dislocation density increases. The FE-SEM images showed that the surface of the thin films is uniform, homogeneous and without cracks. The average sizes of the grains are at the range of 210–235 nm. The obtained values for optical band gap have been in the range of 2.18–2.41 eV, where the value of optical band gap for the thin films decreases by increasing substrate temperature. The Urbach energies of the thin films increase as the substrate temperature is increased. When substrate temperature increased from 400 to 550 °C, electrical resistivity increased from 531 to 2817 Ω cm, carrier concentration decreased from 15.96 × 1014 to 3.71 × 1014 cm−3, Hall mobility decreased from 7.37 to 5.98 cm2/V s. Hall effect analysis indicated that the thin films exhibited n-type conductivity.

Titanium-Niobium Alloy Thin Films at Substrate Temperature (100C,200C and 300C) using Field Emission Scanning Electron Microscopy

This study reports on microstructural characteristics of Titanium-Niobium thin films deposited by RF Magnetron sputtering on glass substrate as a function of substrate temperature. The salient features of Ti-Nb films have been investigated by using high quality images of Field emission scanning electron microscopy (FESEM) and EDX, which enables the study of the film microstructure, elemental composition and grain size. The grain size is found to be sensitive to the Nb content at all substrate temperatures studied for all compositions. Further, the Grain size also exhibited the composition dependence; it reduces drastically from 114 nm for alloy Ti90Nb10 to 21 nm for alloy Ti50Nb50. EDX analysis of the thin film samples validates their elemental composition.

Deposition of 2‐oxazoline‐based plasma polymer coatings using atmospheric pressure helium plasma jet

AbstractWe report on the use of helium plasma jet for plasma polymerisation of 2‐methyl‐2‐oxazoline (OX) on heated silicon substrates. The X‐ray photo electron spectroscopy (XPS) characterisation shows a substantial improvement in film stability in buffer solution when depositing at temperatures above 50°C. Principal component analysis of the time‐of‐flight–secondary ion mass spectrometry data shows excellent correlation with the XPS results, providing insights into the degree of crosslinking in the plasma coatings as a function of substrate temperature. Atomic force microscopy images showed the topography of OX plasma polymer coatings deposited at 80°C and 120°C to be smoother with lower surface roughness values compared to those produced at 50°C. Finally, an 80% reduction in the adhesion of Staphylococcus epidermidis is achieved at the centre of the plasma coatings deposited at 120°C.

A study of the electronic and physical properties of SnO2 thin films as a function of substrate temperature

Abstract In this work, tin dioxide (SnO2) thin films were prepared at various substrate temperatures (380–440 °C, in steps of 20 °C) on glass substrates by the Spray Pyrolysis Method. X-ray Diffraction (XRD) measurements revealed that the SnO2 thin films were formed in a tetragonal crystallized structure. The electronic structure of the tin dioxide thin films that were prepared at several substrate temperatures were investigated with the collected X-ray Absorption Spectroscopy (XAS) data. The crystal structure analysis was also supported by the Extended X-ray Absorption Fine Structure (EXAFS) data analysis extracted from the X-ray Absorption Fine Structure (XAFS) data. Unstable crystal behaviors were detected in the samples due to metastable SnO structure formations as a result of phase transitions from the SnO to SnO2 structure during the annealing processes. Clear information on the atomic displacements in the samples as a picture of the crystal mechanism was obtained from the analysis of EXAFS data. The SnO2 thin films were found to exhibit high transmittance (average 90%) in the 400–1100 nm interval. The thickness of the SnO2 thin film (t) and refractive index (n) were calculated from transmittance spectra in the visible region using envelope method. The direct energy band gaps of the films obtained were 4.01–4.09 eV. Atomic force microscope (AFM) measurements were performed in order to investigate the surface roughness of the SnO2 thin films.

Effects of growth temperature on the photovoltaic properties of RF sputtered undoped NiO thin films

Abstract In this study, nickel oxide (NiO) thin films were deposited on soda lime glass using radio-frequency magnetron sputtering at different growth (substrate) temperatures ranging from room temperature (RT) to 400 °C. The effects of substrate temperature on the structural, morphological, electrical, and optical properties were investigated. The XRD pattern unveiled a dominant peak with (2 0 0) preferential orientations for the film grown at 100 °C. However, for samples grown at high temperatures, a gradual decrease of (2 0 0) peak intensity was observed, which may be the result of the decomposition of NiO as confirmed via EDX. Surface morphology from FESEM revealed that grains were randomly orientated on the surface with maximum grain size of 19.43 nm. Upon increasing the growth temperature, the crystal quality and grain size substantially deteriorated, which is consistent with the XRD results. Scanning probe microscopy (SPM) finds rough surface with the highest surface roughness obtained at RT with a value of 1.232 nm. Electrical resistivity was found to be highly dependent on the growth temperature that decreases from 2150 Ω cm to 72 Ω cm as the substrate temperature increases. For optical properties, the optical bandgap of the NiO films decreases from 3.8 eV to 3.2 eV as a function of substrate temperature as derived from the optical transmittance data. Results show the potential application of the NiO films in photovoltaic devices.

Effect of substrate temperature on the properties of SnS2 thin films

Tin disulfide (SnS2) thin films deposited on glass substrates at various substrate temperatures 300, 325, 350 and 375 °C by the spray pyrolysis technique. Evolutions of the microstructure, surface morphology, optical and electrical properties of the SnS2 thin films as a function of substrate temperature were analyzed. X-ray diffraction (XRD) showed that the deposited films on the TS < 350 °C have a mixture of phase SnS2 and Sn2S3, while those prepared at Ts ≥ 350 °C exhibited the formation just the pure SnS2 phase with hexagonal structure. The mean crystallite size increased from 5.18 to 15.59 nm with increasing substrate temperature from 300 to 350 °C. The morphologies of SnS2 films were significantly affected by the substrate temperature. The optical band gap energy varies from 2.55 to 1.82 eV with the substrate temperatures. Film thickness (d) and optical constants such as refractive index (n), extinction coefficient (k) and dielectric constant (ε) were obtained with the seed preprocessing Pattern search (spPS) technique. Using the measured absorption coefficient data, we estimated the expected absorption capacity and photocurrent of the SnS2 thin films. The photocurrent density Jph was found to be 33 mA/cm2 for Ts ≥ 350 °C. Hall Effect measurements confirm the n-type nature of the as-deposited thin films. The resistivity of the SnS2 thin films decreased from 1.12 × 10+2 to 2.74 × 10−2 Ω.cm as the substrate temperature increased from 300 to 350 °C due to the increased carrier concentration and Hall mobility.

Surface oxidation model in plasma enhanced atomic layer deposition for silicon oxide films including various aminosilane precursors

In this study, a surface oxidation model for the plasma enhanced atomic layer deposition process for silicon oxide films formed by the combination of aminosilane with Ar/O2 plasma is proposed. After the discussion of the dominant oxidation pathways involving both reactive species generation and reaction energy barriers, the authors develop a surface oxidation model and compare it with experimental deposition results. From plasma simulation results, they confirmed two dominant species generated by Ar/O2 plasma; triplet oxygen atom (3O) and singlet oxygen molecule (1O2). The authors then compared the reaction energy barrier along the oxidation pathways for these oxidation species and the corresponding surface terminations by using density functional theory calculations. The calculated activation barriers were negligible in the oxidation paths with 3O, but not in the ones with 1O2. These results support that oxidation by 3O was dominant, especially at low substrate temperatures. The authors suggest a surface oxidation model having two kinds of surface terminations; hydrogen terminations (Si–H) and amino ligand terminations (Si–R). This model can explain the experimental saturation curve for surface oxidation against plasma irradiation time as a function of substrate temperature. The authors confirmed that saturation trends observed with various aminosilane precursors can successfully be explained by their differing ratios of Si–H and Si–R bonds present prior to oxidation.In this study, a surface oxidation model for the plasma enhanced atomic layer deposition process for silicon oxide films formed by the combination of aminosilane with Ar/O2 plasma is proposed. After the discussion of the dominant oxidation pathways involving both reactive species generation and reaction energy barriers, the authors develop a surface oxidation model and compare it with experimental deposition results. From plasma simulation results, they confirmed two dominant species generated by Ar/O2 plasma; triplet oxygen atom (3O) and singlet oxygen molecule (1O2). The authors then compared the reaction energy barrier along the oxidation pathways for these oxidation species and the corresponding surface terminations by using density functional theory calculations. The calculated activation barriers were negligible in the oxidation paths with 3O, but not in the ones with 1O2. These results support that oxidation by 3O was dominant, especially at low substrate temperatures. The authors suggest a surface...

Real-time in situ ellipsometric monitoring of aluminum nitride film growth via hollow-cathode plasma-assisted atomic layer deposition

The authors report on the real-time monitoring of self-limiting aluminum nitride growth process by using multiwavelength in situ ellipsometry. Aluminum nitride (AlN) thin films were grown on Si(100) substrates via hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD) using trimethylaluminum (TMA) and Ar/N2/H2 plasma as metal precursor and coreactant, respectively. Growth saturation experiments within 100–250 °C temperature range were carried out without interruption as extended single runs featuring 10-cycle subruns for each parameter change. The sensitivity of the multiwavelength ellipsometry provided sufficient resolution to observe not only the minuscule changes in the growth-per-cycle (GPC) parameter, but also the single chemical adsorption (chemisorption) and plasma-assisted ligand removal events. GPC values showed a slight increasing slope within 100–200 °C, followed by a stronger surge at 250 °C, signaling the onset of thermal decomposition. The real-time dynamic in situ monitoring revealed mainly the following insights into the HCPA-ALD process of AlN: (i) film growth rate and TMA chemisorption amount exhibited plasma power dependent saturation behavior, which was also correlated with the substrate temperature; (ii) time-dependent refractive index evolution indicated a nonconstant relationship: a faster increase within the first ∼100 cycles followed by a slower increase as the AlN film gets thicker; and (iii) a considerable improvement in crystallinity was observed when the substrate temperature exceeded 200 °C. Besides in situ optical characterization, ex situ optical, structural, and chemical characterization studies were also carried out on 500-cycle grown AlN films as a function of substrate temperature. All AlN samples displayed a single-phase wurtzite polycrystalline character with no detectable carbon and relatively low (&amp;lt;5%) oxygen content within the bulk of the films. Moreover, regardless of the deposition temperature, HCPA-ALD grown AlN films exhibited highly stoichiometric elemental composition.

Surface oxidation model in plasma enhanced atomic layer deposition for silicon oxide films including various aminosilane precursors

In this study, a surface oxidation model for the plasma enhanced atomic layer deposition process for silicon oxide films formed by the combination of aminosilane with Ar/O2 plasma is proposed. After the discussion of the dominant oxidation pathways involving both reactive species generation and reaction energy barriers, the authors develop a surface oxidation model and compare it with experimental deposition results. From plasma simulation results, they confirmed two dominant species generated by Ar/O2 plasma; triplet oxygen atom (3O) and singlet oxygen molecule (1O2). The authors then compared the reaction energy barrier along the oxidation pathways for these oxidation species and the corresponding surface terminations by using density functional theory calculations. The calculated activation barriers were negligible in the oxidation paths with 3O, but not in the ones with 1O2. These results support that oxidation by 3O was dominant, especially at low substrate temperatures. The authors suggest a surface oxidation model having two kinds of surface terminations; hydrogen terminations (Si–H) and amino ligand terminations (Si–R). This model can explain the experimental saturation curve for surface oxidation against plasma irradiation time as a function of substrate temperature. The authors confirmed that saturation trends observed with various aminosilane precursors can successfully be explained by their differing ratios of Si–H and Si–R bonds present prior to oxidation.

Effects of substrate temperature and precursor amount on optical properties and microstructure of CVD deposited amorphous TiO2 thin films

In this research, TiO2 thin films were deposited on glass substrate by chemical vapor deposition using tetra isopropylorthotitanate as a precursor at low temperature. The TiO2thin films were formed without using an oxygen source or annealing. Effects of substrate temperature and amount of the precursor on surface microstructure and optical properties of deposited TiO2 thin films were investigated. X-ray diffraction (XRD), UV-visible spectrophotometry and atomic force microscopy (AFM) were used to analyze the fabricated layers. The XRD analysis revealed that structure of all prepared layers was in amorphous phase. Analysis of AFM images showed that by increasing substrate temperature, the layer surfaces became rougher and simultaneously nanoparticle size was more uniform. Texture analysis revealed that increasing substrate temperature and decreasing precursor amount both increased surface isotropy. Thickness of layers was calculated by applying the Swanepoel method to the transmittance spectra. Variations in optical parameters were studied, including of optical band gap, refractive index, extinction coefficient, complex dielectric function, Urbach energy, single oscillator energy and dispersion energy. The results indicated that optical properties were functions of substrate temperature and precursor amount.

Modeling Diffusion of Impurities in Molybdenum Thin Films as a Function of Substrate Temperature

Alkali ions are key to improving the performance of polycrystalline Cu(In,Ga)Se2 (CIGS) solar cells. Typically, a soda–lime glass substrate acts as an intrinsic source for many alkali ions. For these ions to reach the CIGS layer, diffusion through a metallic back contact is necessary. Typically deposited via sputtering, the morphology of this metallic back contact is dependent on multiple deposition parameters, including substrate temperature. By preparing films with varying deposition parameters, and utilizing both, multiple material characterizations (X-ray diffraction, scanning electron microscopy, and secondary ion mass spectrometry) and numerical modeling, we demonstrate here that effective paths of diffusion are just as important as diffusion rate for the alkali ions. As the substrate temperature increases, the mechanism that hinders the ability for alkali ions to diffuse switches effectively from diffusion rate to effective path of diffusion. It is shown that the lack of viable diffusion paths at substrate temperatures above 100 °C becomes the dominant factor for the transport of alkali ions.