Sample Tilt Angle Research Articles

Maskless photolithography based on ultraviolet micro-LEDs and direct writing method for improving pattern resolution

Ultraviolet micro-LEDs show great potential as a light source for maskless photolithography. However, there are few reports on micro-LED based maskless photolithography systems, and the studies on the effects of system parameters on exposure patterns are still lacking. Hence, we developed a maskless photolithography system that employs micro-LEDs with peak wavelength 375 nm to produce micrometer-sized exposure patterns in photoresists. We also systematically explored the effects of exposure time and current density of micro-LED on static direct writing patterns, as well as the effects of stage velocity and current pulse width on dynamic direct writing patterns. Furthermore, reducing the size of micro-LED pixels enables obtaining high-resolution exposure patterns, but this approach will bring technical challenges and high costs. Therefore, this paper proposes an oblique direct writing method that, instead of reducing the micro-LED pixel size, improves the pattern resolution by changing the tilt angle of the sample. The experimental results show that the linewidths of the exposed lines decreased by 4.0% and 15.2%, respectively, as the sample tilt angle increased from 0° to 15° and 30°, which confirms the feasibility of the proposed method to improve the pattern resolution. This method is also expected to correct the exposure pattern error caused by optical distortion of the lens in the photolithography system. The system and method reported can be applied in various fields such as PCBs, photovoltaics, solar cells, and MEMS.

(Digital Presentation) Characterization of Anisotropic Strain in Anelastic Material By Raman Spectroscopy

Raman spectroscopy has recently been applied for non-destructive characterization of strain in crystalline thin films. It makes use of the numerical value of the mode Grüneisen parameter γ , which equals (minus) the ratio of the relative change in the frequency of a Raman-active vibrational mode and the strain-induced relative change in the unit cell volume. In the presence of in-plane, compressive biaxial strain, aliovalent doped CeO2-films exhibit values of γ which are ~30% smaller than the literature values for the bulk ceramics under isostatic stress. This discrepancy is due in large part to the negative contribution from the anelastic (time-dependent) mechanical properties of oxygen-deficient ceria, thereby raising questions concerning the relationship between Raman mode frequency and anelastic strain. Here we propose a way to "separate" anelastic and elastic contributions to the Grüneisen parameter.500-650nm thick films , x=0.1-0.2, were deposited by RF magnetron sputtering on (100) p-Si wafers (1Ω-cm, tSi=280mm). The films (S-films) were in the fluorite phase with pronounced (111) texture and exhibited biaxial , compressive strain. The in- and out-of-plane lattice parameters (aS || , aS ⊥ ) of the S-films were determined by XRD at different sample tilt angles. The in-plane stress (σbi) in the S-films was determined by profilometry from the change in Si-wafer curvature following film deposition. From σbi and the film biaxial modulus, the elastic component of the in-plane compressive strain (ue ) was calculated (~ -0.2%).Strain-free (relaxed) R-films were obtained by partial substrate removal, forming 2 mm diameter self-supported membranes. Pronounced membrane buckling indicated that residual strain was negligible (aR || ≈ aR ^ ). From the increase in area upon substrate removal, measured with optical profilometry, the total S-film in-plane strain (ut ) was calculated from aS ||/aR-1 ≈ -0.5%. The anelastic strain component may be calculated as ua= ut-ue . The small, anisotropic strain-induced blue shift of the frequency of the F2g -phonon mode for S-films suggests that the F2g mode responds primarily to the elastic component of the strain.As a control, 430nm thick films of mechanically elastic Y2O3 were deposited by sputtering on a Si wafer covered with a 1.5 µm thick PECVD deposited SiO2 layer. This layer supported the Y2O3-films upon membrane formation, but prevented complete strain relaxation. The Y2O3-films were in the double fluorite phase with strong (222) texture and, as with the S-films, were under in-plane compressive strain. The Y2O3 S-film lattice parameters were determined by acquiring XRD-patterns at different sample tilt angles, while membrane in- and out-of-plane lattice parameters were determined with XRD in the transmission and reflection modes, respectively. The values of γ calculated from the Raman frequency of the [Fg +Ag ] peak position were close to the literature values for bulk yttria under isostatic stress.This work should serve as a sample protocol for strain characterization of doped ceria thin films. It supports the concept that the discrepancy between the behavior of Raman modes of isostatically and anisotropically strained doped ceria is related to anelasticity. Our results shed light upon strain characterization by Raman spectroscopy and may lay the foundation for future studies to elucidate selective sensitivity to various strain components.

Random conical tilt reconstruction without particle picking in cryo-electron microscopy.

A method is proposed to reconstruct the 3D molecular structure from micrographs collected at just one sample tilt angle in the random conical tilt scheme in cryo-electron microscopy. The method uses autocorrelation analysis on the micrographs to estimate features of the molecule which are invariant under certain nuisance parameters such as the positions of molecular projections in the micrographs. This enables the molecular structure to be reconstructed directly from micrographs, completely circumventing the need for particle picking. Reconstructions are demonstrated with simulated data and the effect of the missing-cone region is investigated. These results show promise to reduce the size limit for single-particle reconstruction in cryo-electron microscopy.

Femtosecond pulsed laser ablation for paint removal at oblique illumination: Effect of the incidence angle

This research studies how the angle of incidence affects the ablation process when a pulsed femtosecond laser with a wavelength of 1040 nm and a high repetition rate is applied to spray paints used for graffiti. Flat test samples were painted using four different spray paints (red, blue, black and silver). All paints had an organic base but different physicochemical properties. For each paint, the ablation process was characterized using confocal microscopy, determining the threshold fluence and the penetration depth of the laser radiation at normal incidence. For different sample tilt angles in the range of 0°–60°, the effect of oblique incidence was analysed in terms of its effect on the ablation rate and the geometric properties (depth and width) of the ablation grooves on each paint. The results show a clear decrease in the ablation rate as the angle of incidence moves away from normal incidence. Moreover, it can also be observed that for a given angle, groove depth is the property most affected by beam tilt. These results represent a necessary step in addressing both cleaning and other laser ablation processes on non-flat surfaces in a controlled and reproducible manner.

X-ray elastic constants determined by the combination of sin2 ψ and substrate-curvature methods

Abstract A new methodology is presented that allows the quantification of experimental X-ray elastic constants of polycrystalline thin films without use of special diffractometer attachments. The approach is based on the combination of sin2 ψ and curvature methods. The elastic strains in the polycrystalline films are characterized by the measurement of lattice spacings at different sample tilt angles, while the macroscopic stress in the film is calculated from the substrate curvature applying the Stoney formula. The radius of the curvature is determined from a sequence of rocking curves measured at different sample positions. The method is demonstrated on Al thin films deposited on Si(100) substrates. The X-ray diffraction measurements were performed at the synchrotron source BESSY in Berlin.

Calibration of crystal orientation and pattern center of EBSD using integrated digital image correlation

The accuracy of electron backscatter diffraction indexation has long been limited by pattern center determination, and numerous hardware and software methods have been proposed to improve the calibration. Here, an Integrated Digital Image Correlation (IDIC) procedure is proposed to determine simultaneously crystal orientation and pattern center by registering experimental and simulated electron diffraction patterns. To assess the performance and robustness of the procedure, numerous case studies are reported. Noise sensitivity is first explored on virtual data to assess convergence conditions and result uncertainty up to high noise level and small detector size. Two experimental data sets are further exploited. First, a high-definition detector shows that crystal orientation uncertainty as low as 3×10−2 degrees can be achieved, that is at least 80% less than commercial Hough-transformation based indexation method. Different sample tilt angles are tested, IDIC indexation proves much more tolerant with imprecise tilt angles than common EBSD indexation methods. Second, fast EBSD acquisitions with a coarse definition performed during an in-situ tensile test are analysed. A quantification of the residual noise allows one to formulate an optimized IDIC functional with a proper pixel-wise weight. With the latter refinement a two-pass procedure leads to a much enhanced precision of the determination of crystal orientation, giving access to more precise evaluation of maps of geometrically necessary dislocation densities.

Off-axis electron holography of Néel-type skyrmions in multilayers of heavy metals and ferromagnets

Magnetic skyrmions are complex swirling spin structures that are of interest for applications in energy-efficient memories and logic technologies. Multilayers of heavy metals and ferromagnets have been shown to host magnetic skyrmions at room temperature. Lorentz transmission electron microscopy is often used to study magnetic domain structures in multilayer samples using mainly Fresnel defocus imaging. Here, off-axis electron holography is used to obtain in-focus electron optical phase images of Néel-type domains and skyrmions in an Ir/Fe/Co/Pt multilayer sample. The preparation of the sample, reconstruction of the holograms and influence of sample tilt angle on the signal-to-noise ratio in the phase images are discussed. A good agreement is found between images of individual skyrmions that are stabilized using an external magnetic field and simulated images based on theoretical models of Néel-type skyrmions.

Analysis of nanometer-sized aligned conical pores using small-angle x-ray scattering

Small angle X-ray scattering (SAXS) was used to quantitatively study the morphology of aligned, mono-disperse conical etched ion tracks in thin films of amorphous silicon dioxide with aspect ratios of around 6:1, and in polycarbonate foils with aspect ratios of around 1000:1. This paper presents the measurement procedure and methods developed for the analysis of the scattering images and shows results obtained for the two material systems. To enable accurate parameter extraction from the data collected from conical scattering objects a model fitting the 2-D detector images was developed. The analysis involved fitting images from a sequence of measurements with different sample tilts to minimise errors which may have been introduced due to the experimental set-up. The model was validated by the exploitation of the geometric relationship between the sample tilt angle and the cone opening angle, to an angle observed in the features of the SAXS images. We also demonstrate that a fitting procedure for 1-D data extracted from the scattering images using a hard cylinder model can also be used to extract the cone size. The application of these techniques enables us to reconstruct the cone morphologies with unprecedented precision.

Effect of Sample Tilt on Spherical Indentation of an Elastic Solid

Abstract The effect of sample tilt in spherical indentation is studied by recourse to three-dimensional finite element simulation of the loading process. An elastic solid subjected to a rigid spherical indenter is considered under either frictionless or infinitely frictional contact condition. It is found the contact boundary is not parallel with the tilted surface, and the tilt angle of the contact boundary is smaller than the sample tilt angle. The side force is prominent for frictionless contact, and the ratio of side force to normal force increases with the sample tilt angle because of a larger unbalanced displacement field. Nevertheless, the ratio of side force to normal force is relatively small for infinitely frictional contact because the displacement distribution is controlled by the nonslip condition and almost balanced irrespective of sample tilt.

Optimization of the FIB Preparation on Polycrystalline Al Materials through the Orientation Determination by EBSD

Abstract For the assessment of the precipitation state in aluminum-based alloys by transmission electron microscopy (TEM), the sample must have an orientation in the [100] direction of the matrix. TEMs equipped with objective lenses that are optimized for high resolution are mostly characterized by limited sample tilt angles. The required crystal orientation must thus be taken into account during sampling. A favorably oriented grain was chosen in a coarse-grained material using electron backscatter diffraction and prepared in a suitable direction applying the in-situ lift-out method in the focused ion beam device. After that, the final correction of the orientation in the TEM amounts to less than 12°.

Charge deposition dependence of electron transmission through PET nanocapillaries and a tapered glass microcapillary

Abstract Charge deposition dependences of electron transmission through insulating PET nanocapillaries and a tapered glass microcapillary are reported and differences with HCI transmission are noted. Investigations were conducted for electrons with incident energies 500–1000 eV, corresponding to energies per charge similar to those used for HCI studies, incident on (1) an array of PET nanocapillaries (density ∼5 × 108/cm2) with diameters 100 nm in a foil of thickness 12 μm, and (2) on a tapered glass microcapillary with inlet/outlet diameters of 800/100 μm and a length of ∼35 mm. The transmission was measured for incident electrons at small sample tilt angles ranging from 0° to 5° with respect to the beam direction. For most angles, including those near zero degrees, there was an initial quiet period during which essentially no transmission was observed, followed by large rises in the transmission during relatively short periods of charge deposition before equilibrium of the transmission was reached. The resulting equilibrium was stable, blocked or had frequent oscillations depending on the incident energy and the capillary used. Observations for both capillaries show that a negative charge patch is needed to guide incident electrons through the capillaries similar to the manner in which HCIs are guided through capillaries.

Determination of domain wall chirality using in situ Lorentz transmission electron microscopy

Controlling domain wall chirality is increasingly seen in non-centrosymmetric materials. Mapping chiral magnetic domains requires knowledge about all the vector components of the magnetization, which poses a problem for conventional Lorentz transmission electron microscopy (LTEM) that is only sensitive to magnetic fields perpendicular to the electron beams direction of travel. The standard approach in LTEM for determining the third component of the magnetization is to tilt the sample to some angle and record a second image. This presents a problem for any domain structures that are stabilized by an applied external magnetic field (e.g. skyrmions), because the standard LTEM setup does not allow independent control of the angle of an applied magnetic field, and sample tilt angle. Here we show that applying a modified transport of intensity equation analysis to LTEM images collected during an applied field sweep, we can determine the domain wall chirality of labyrinth domains in a perpendicularly magnetized material, avoiding the need to tilt the sample.

Precision and accuracy of stress measurement with a portable X-ray machine using an area detector

The use of portable X-ray stress analyzers, which utilize an area detector along with the newly adopted `cosα' or full-ring fitting method, has recently attracted increasing interest. In laboratory conditions, these measurements are fast, convenient and precise because they employ a single-exposure technique that does not require sample rotation. In addition, the effects of grain size and orientation can be evaluated from the Debye ring recorded on the area detector prior to data analysis. The accuracy of the measured stress, however, has been questioned because in most cases just a single reflection is analyzed and the sample-to-detector distances are relatively short. This article presents a comprehensive analysis of the uncertainty associated with a state-of-the-art commercial portable X-ray device. Annealed ferrite reference powders were used to quantify the instrument precision, and the accuracy of the stress measurement was tested by in situ tensile loading on 1018 carbon steel and 6061 aluminium alloy bar samples. The results show that the precision and accuracy are sensitive to the instrument (or sample) tilt angle (ψ0) as well as to the selected hkl reflection of the sample. The instrument, sample and data analysis methods all affect the overall uncertainty, and each contribution is described for this specific portable X-ray system. Finally, on the basis of the conclusions reached, desirable measurement/analysis protocols for accurate stress assessments are also presented.

Electron-beam transmission through a micrometer-sized tapered-glass capillary: Dependence on incident energy and angular tilt angle

An experimental study of 500- and 1000-eV incident electrons transmitted through a micrometer-sized funnel-shaped (tapered) glass capillary with inlet diameter 0.80 mm, outlet diameter 0.10 mm, and a length of 35 mm is reported. The properties of the electron beam transmitted were measured as a function of the emerging angle and the incident energy dependence. The angular profiles were found to be comprised of up to three peaks for both 500 and 1000 eV showing evidence for transmission going straight through the capillary without interacting with the walls (direct), as well as transmission resulting from Coulomb deflection of the electrons from a negative charge patch or by scattering from nuclei close to the surface of the capillary (indirect). The energy spectra show that elastically transmitted electrons dominate at 500 eV for increasing sample tilt angles up to \ensuremath{\sim}5.0\ifmmode^\circ\else\textdegree\fi{}, while inelastic processes dominate for 1000 eV already at tilt angles of \ensuremath{\sim}1.0\ifmmode^\circ\else\textdegree\fi{}. The angular width of the emitted electrons was found to constitute a narrow beam for direct (\ensuremath{\sim}0.4\ifmmode^\circ\else\textdegree\fi{}) and indirect (0.6\ifmmode^\circ\else\textdegree\fi{} for 500 eV and 1.0\ifmmode^\circ\else\textdegree\fi{} for 1000 eV) transmission for both energies with the widths decreasing for the largest tilt angles measured and approaching the inherent resolution (\ensuremath{\sim}0.3\ifmmode^\circ\else\textdegree\fi{}) of the electron analyzer.

Implementing Transmission Electron Backscatter Diffraction for Atom Probe Tomography

There are advantages to performing transmission electron backscattering diffraction (tEBSD) in conjunction with focused ion beam-based specimen preparation for atom probe tomography (APT). Although tEBSD allows users to identify the position and character of grain boundaries, which can then be combined with APT to provide full chemical and orientation characterization of grain boundaries, tEBSD can also provide imaging information that improves the APT specimen preparation process by insuring proper placement of the targeted grain boundary within an APT specimen. In this report we discuss sample tilt angles, ion beam milling energies, and other considerations to optimize Kikuchi diffraction pattern quality for the APT specimen geometry. Coordinated specimen preparation and analysis of a grain boundary in a Ni-based Inconel 600 alloy is used to illustrate the approach revealing a 50° misorientation and trace element segregation to the grain boundary.

Photoelectronic Effects with Graphene Channels Interfaced with Quantum Dots Arrays

The electrical and photo-electronic properties of graphene-based field effect transistors (GFETs) were studied when the single layer graphene served as the transistor channel, while interfaced with well organized, isolated semiconductor quantum dots (QD) array. The photoluminescence (PL) of the QDs as a function of the drain-source (Vds) and the gate-source (Vgs) bias was studied. Graphene, a two-dimensional, single layer thick crystalline form of carbon atoms, has outstanding physical properties, such as high conductivity, chemical inertness, mechanical robustness and unusual dispersion relations [1]. In the past, we studied graphene layer(s) when suspended over nano-pore structures [2-6]. Here we used anodized aluminum oxide (AAO) as the perforated substrate, and core/shell CdSe/ZnS semiconductor quantum dots (QD) as the photo-sensitive material. The QD were imbedded in the AAO pores. The GFETs were fabricated by transferring a single layer of graphene on top of the QD imbedded AAO. The array of holes on the AAO substrate were 25-30 nm in diameter and with a pitch of 100 nm. For the photoluminescence (PL) measurements, a 10 mW Ar ion laser at 488 nm was used in confocal arrangement. Coupling of the incident and/or emitted light with the surface Plasmon/Polariton (SPP) mode was observed as a peak in PL curve as a function of the sample's tilt angle with respect to the incident optical beam. The fluorescence peak of the QDs decreased monotonously as a function of Vgs and Vds alluding to the control of PL by the biasing potentials. The effect of white-light intensity on the sample conductivity was studied, as well: the difference in Ids between illuminated and non-illuminated cases was substantially affected by the biasing potentials. [1] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva and A.A. Firsov, “ Electric Field Effect in Atomically Thin Carbon Films”, Science, 306, 666 (2004). [2] A. Banerjee, R. Li and H. Grebel, “Surface Enhanced Raman with Graphenated Anodized Aluminum Oxide Substrates: the Effect of Sub-Wavelength Patterns”, Nanotechnology, 20 (29), art. no. 295502 (2009). [3] A. Banerjee and H. Grebel, “Depositing Graphene Films on Solid and Perforated Substrates”, Nanotechnology, 19 1-5 art. no. 365303 (2008). [4] Ruiqiong Li, and Grebel Haim, “Surface Enhanced Fluorescence”, IEEE Sensors, 10(3), 465-468 (2010) doi: 10.1109/JSEN.2009.2038513. [5] R. Li, A. Banerjee and H. Grebel, “The possibility for surface plasmon lasers”, Optics Express, 17, 1622-1627 (2009). [6] A. Banerjee, R. Li and H. Grebel, "Surface plasmon lasers with quantum dots as gain media", Appl. Phys. Letts., 95, 251106 (2009); doi:10.1063/1.3276273.

Elastic and inelastic transmission of electrons through insulating polyethylene terephthalate nanocapillaries

The transmission of electrons with incident energies of 300, 500, and 800 eV through insulating polyethylene terephthalate (PET) nanocapillaries for small tilt angles near 0\ifmmode^\circ\else\textdegree\fi{} was studied. The exiting electrons showed elastic and inelastic behaviors with the inelasticity increasing with the tilt angle. This paper is an extension of our earlier work for electrons on PET reported by Das et al. [Phys. Rev. A 76, 042716 (2007)], but the present study goes further by investigating the transmission for very small tilt angles near 0\ifmmode^\circ\else\textdegree\fi{} with the small step sizes revealing distinct regions of behavior. The work performed here was conducted for two samples with different capillary diameters and pore densities: sample 1 with 100-nm diameter capillaries in a foil of 12-\textmu{}m thickness and a pore density of $5\ifmmode\times\else\texttimes\fi{}{10}^{8}/{\mathrm{cm}}^{2}$, and sample 2 with 200-nm diameter capillaries with the same foil thickness and a pore density of $5\ifmmode\times\else\texttimes\fi{}{10}^{7}/{\mathrm{cm}}^{2}$. Two distinct regions of transmission depending on the sample tilt angle for both samples corresponding to direct and guided electrons as well as the transition region between them were observed. The angular centers and widths of the transmission for each angle investigated were found and are discussed in terms of the tilt angle variation in the foil. For the widths, comparison with the inherent angular width of the electron spectrometer is made. Energy loss of electrons was studied from the centroids of the energy spectra with these energies corresponding to the peak centers of the angular profiles. The broadness of the energy distributions due to inelasticity was investigated from the full width at half maxima (in eV) of the spectra. The results for both samples agreed well despite the differences in capillary diameters and pore densities. The results are in partial agreement with the previous work performed for PET nanocapillaries by Das et al. [Phys. Rev. A 76, 042716 (2007)], but differences are also found.

3D scanning SAXS: A novel method for the assessment of bone ultrastructure orientation

The arrangement and orientation of the ultrastructure plays an important role for the mechanical properties of inhomogeneous and anisotropic materials, such as polymers, wood, or bone. However, there is a lack of techniques to spatially resolve and quantify the material's ultrastructure orientation in a macroscopic context. In this study, a new method is presented, which allows deriving the ultrastructural 3D orientation in a quantitative and spatially resolved manner. The proposed 3D scanning small-angle X-ray scattering (3D sSAXS) method was demonstrated on a thin trabecular bone specimen of a human vertebra. A micro-focus X-ray beam from a synchrotron radiation source was used to raster scan the sample for different rotation angles. Furthermore, a mathematical framework was developed, validated and employed to describe the relation between the SAXS data for the different rotation angles and the local 3D orientation and degree of orientation (DO) of the bone ultrastructure. The resulting local 3D orientation was visualized by a 3D orientation map using vector fields. Finally, by applying the proposed 3D scanning SAXS method on consecutive bone sections, a 3D map of the local orientation of a complete trabecular element could be reconstructed for the first time. The obtained 3D orientation map provided information on the bone ultrastructure organization and revealed links between trabecular bone microarchitecture and local bone ultrastructure. More specifically, we observed that trabecular bone ultrastructure is organized in orientation domains of tens of micrometers in size. In addition, it was observed that domains with a high DO were more likely to be found near the surface of the trabecular structure, and domains with lower DO (or transition zones) were located in-between the domains with high DO. The method reproducibility was validated by comparing the results obtained when scanning the sample under different sample tilt angles. 3D orientation maps such as the ones created using 3D scanning SAXS will help to quantify and understand structure–function relationships between bone ultrastructure and bone mechanics. Beyond that, the proposed method can also be used in other research fields such as material sciences, with the aim to locally determine the 3D orientation of material components.

3D grain orientation mapping of nanocrystalline materials in the TEM

Nanocrystalline materials (i.e. polycrystalline aggregates where the individual crystallites/grains or particles have sizes below 100 nm) are formed through various processes ranging from mechanical treatments of bulk materials, to electrodeposition of thin films and coatings to aggregation of nanoparticles. The materials constitute one of the most rapidly growing new classes of materials and exhibit enhanced properties, see e.g. [1,2], ranging from high strength and wear resistance, to unique functional characteristics, which open up a large spectrum of applications e.g. for micro- and nano-electro-mechanical systems (MEMS and NEMS). Consequently, materials models tend to be based only on simple observables such as a 2D crystalline projection or an average grain/particle size. Motivated by this, a new and non-destructive technique called "3D-Orientation Mapping in TEM" (3D-OMiTEM) was developed and it was demonstrated that both orientation and 3D morphology of ~1000 individual nanograins could be measured with spatial and angular resolutions of 1 nm and 1 degree [3]. Notably, the foil may have five or more grains stacked on top of each other in the thickness direction. Technically speaking, 3D-OMiTEM is based on conical-scanning dark-field imaging. By recording images at a series of different beam and sample tilt angles it is possible to reconstruct the complete 3D orientation map of nanograins or nanoparticles. With the availability of 3D-OMiTEM crystallographic orientation relationships, interface curvatures, 3D connectivity between nanograins or nanoparticles as well as evolution of 3D structures e.g. during heat treatments or deformation steps, can be addressed for the first time in nanocrystalline materials. An overview of the methodology and latest results is given.

Fiber texture of sputter deposited molybdenum films and structural zone model

The texture orientation of 2.5, 5, and 100 nm thick Mo films grown by sputter deposition on SiO2 membranes at room temperature has been studied quantitatively using transmission electron microscopy. The sample tilt angle dependent diffraction patterns of these films revealed a fiber texture with the [110] out-of-plane direction for all film thicknesses. Films grown at different sputtering power and substrate–target distance showed a similar texture orientation. These results would imply that the growth was in zone II, according to the microstructure classification of the structural zone model. This is in contrast to the conventional assignment of zone I for Mo deposition at room temperature based on the low Mo homologous temperature of ∼0.1. It was found that texture dispersion was reduced as the thickness of the film increased. Possible mechanisms, including energetic particles bombardment during growth, which could affect the surface mobility and texture of the films, were discussed.