Influence Of Post-deposition Annealing Research Articles

Effect of post-deposition annealing on the interfacial chemical bonding states and band alignment of atomic layer deposited neodymium oxide on silicon

The influence of post-deposition annealing on the interfacial chemical bonding states and the band offset of Nd2O3/Si is analyzed by x-ray photoelectron spectroscopy (XPS) and variable angle spectroscopic ellipsometry (VASE). By investigating the chemical shifts of the Nd 3d, O 1s and Si 2p core level spectra, it is found that the diffusion of the Si atoms from the substrates to the films occurs, and the interfacial Nd silicate-like configuration is subject to a transformation from Nd2SiO5 to Nd2Si2O7 with the annealing temperature. Moreover, the direct optical band-gap energy obtained from the VASE data shifts to a higher energy with the increasing annealing temperature and varies from 5.86 to 6.24 eV. The valence band spectra of the measured XPS gives the VBO (valance band offset) value of 1.5 eV for the as-grown annealed samples and 3.2 and 3.0 eV for the annealed samples at 700 and 900 °C, respectively. Therefore, the calculated CBO (conduction band offset) are 3.24 eV, 1.85 eV and 2.12 eV for the as-grown and annealed films at 700 °C and 900 °C. The suitable band-gap and band offsets relative to Si make Nd2O3 films one of the promising high-k dielectric candidates.

Investigation of LaAlO 3 /ZrO 2 / a ‐InGaZnO thin‐film transistors using atmospheric pressure plasma jet

Amorphous indium–gallium–zinc-oxide thin-film transistors (a-IGZO-TFTs) with the LaAlO3/ZrO2 gate dielectric stack employing a novel atmospheric pressure plasma jet process that results in small subthreshold swing and low threshold voltage are proposed and fabricated. The influence of post-deposition annealing (PDA) temperature on LaAlO3/ZrO2 gate dielectric stack and device performance was investigated. The equivalent oxide thickness of the LaAlO3/ZrO2 dielectric stack decreases from 11.5 nm without annealing to 7 nm after a 500°C annealing was applied. The LaAlO3/ZrO2/a-InGaZnO TFT with a 500°C annealing exhibits a small subthreshold swing of 77 mV·dec−1, a high field-effect mobility of 9 cm2·V−1·s−1 and an excellent current ratio of 1.8 × 107, which could be attributed to the improved gate dielectric quality by the PDA. The LaAlO3/ZrO2/a-InGaZnO TFTs with excellent gate control ability allow the device to operate at a low operating voltage with low power consumption.

Influence of post-deposition annealing in air and vacuum on the properties of thermally evaporated gallium oxide films

Oxidative annealing in air or reductive annealing in vacuum around 773K of thermally evaporated gallium oxide films produces monoclinic β-Ga2O3 films of distinctly different compositional, optical, morphological and electrical properties. The pristine films prepared by the evaporation of Ga2O3 powders are oxygen deficient, amorphous and absorbing in UV–visible region. The air annealed films are transparent (band gap ∼4.9eV), display nanometric granular morphology and are characterized by <1.0eV extrinsic and 1.2–1.6eV intrinsic activation energies in the Arrhenius plots of electrical conductivity. The growth of Ga2O3 phase on vacuum annealing takes place through the decomposition of Ga2O, one of the constituents of the pristine films. The vacuum annealed films exhibit comparatively lower transparency (band gap <4.5eV), comprise micron-sized dendrites or fibres and have <1.0eV extrinsic and 1.7–2.0eV intrinsic activation energies. The incorporation of these properties results from compositional changes in films induced by annealing in air or vacuum ambient.

Studies of dodecaphenyl polyhedral oligomeric silsesquioxane thin films on Si(1 0 0) wafers

In this work the spectroscopic and microscopic studies of dodecaphenyl POSS thin films are presented. Thin films have been deposited using molecular beam technique. Due to thermal properties – relatively low sublimation temperature and preservation of molecular structure – cage type silsesquioxanes are perfect to fabricate a thin film by means of physical vapor deposition.PhT12 thin films with thickness varying from 40nm up to 100nm, deposited on a Si(100) surface, were studied under high vacuum conditions. The research was focused on the influence of post deposition annealing (from 100°C up to 200°C) on molecular structure as well as thin film roughness and optical properties.A wide range of measuring methods were applied for thin film studies. Fourier Transform Infrared Spectroscopy (FTIR) was used in order to learn molecular structure and stability, Ellipsometry for thin film thickness and uniformity, Grazing Incidence X-ray Diffraction (GIXD) for thin film long range order investigation and finally Atomic Force Microscopy (AFM) for visual confirmation of drawn conclusions.

Effects of Thickness and Annealing on Optoelectronic Properties of Electrodeposited ZnS Thin Films for Photonic Device Applications

Thin layers of ZnS with thicknesses of 400 nm, 500 nm, and 700 nm have been electrodeposited on glass/fluorine-doped tin oxide substrates using a simple two-electrode setup under similar conditions. Structural characterization of the layers using x-ray diffraction (XRD) measurements showed that they were amorphous. The results of optical characterization carried out in the wavelength range of 315 nm to 800 nm using spectrophotometry revealed that the optical properties of the layers are strongly influenced by the film thickness as well as annealing conditions. The values of the refractive index, extinction coefficient, absorption coefficient, and dielectric constant obtained from normal-incidence transmittance spectra were generally lower after annealing, showing also the influence of postdeposition annealing on the deposited ZnS layers. Electrical characterization of the layers, using direct-current current–voltage measurement under dark conditions at room temperature, shows that the resistivity of the as-deposited and annealed layers is in the range of 1.4 × 104 Ω cm to 2.5 × 104 Ω cm and 2.5 × 104 Ω cm to 3.1 × 104 Ω cm, respectively. The results suggest that the optoelectronic properties can be tuned for particular applications by adjusting the thickness of the layers appropriately.

Film properties of low temperature HfO2 grown with H2O, O3, or remote O2-plasma

A reduction of the deposition temperature is necessary for atomic layer deposition (ALD) on organic devices. HfO2 films were deposited by ALD on silicon substrates in a wide temperature range from 80 to 300 °C with tetrakis[ethylmethylamino]hafnium as metal precursor and H2O, O3, or an remote O2-plasma as oxygen source. Growth rate and density were correlated to electrical properties like dielectric constant and leakage current of simple capacitor structures to evaluate the impact of different process conditions. Process optimizations were performed to reduce film imperfections visible at lower deposition temperatures. Additionally, the influence of postdeposition annealing on the structural and electrical properties was studied.

Effects of post-deposition annealing ambient on chemical, structural, and electrical properties of RF magnetron sputtered Y2O3 gate on gallium nitride

The influence of post-deposition annealing (PDA) ambient [O2, Ar, forming gas (FG; 95% N2–5% H2), and N2] on chemical, structural, and electrical properties of RF magnetron sputtered Y2O3 films on gallium nitride (GaN) had been investigated. X-ray photoelectron spectroscopy revealed that the bulk oxide annealed in different ambient was composed of Y–O and Y–N bonds while the interfacial layer (IL) was comprised of a mixture of Ga–O, Y–O, Ga–O–N, and Y–N bonding. It was also detected that oxygen trapping happened in the bulk oxide for all of the investigated samples but this oxygen trapping ensued until the region of IL for sample annealed in O2 ambient. The Y2O3 film subjected to PDA in N2 ambient was in amorphous structure as no Y2O3 phase was able to detect by X-ray diffraction (XRD). When PDA was performed in O2, Ar, and FG ambient, polycrystalline phase of Y2O3 was detected. Besides, XRD results also revealed β-Ga2O3 phase for all samples. A correlation between the chemical and structural results with metal–oxide–semiconductor (MOS) characteristics of Y2O3/GaN structure subjected to different PDA ambient has been established. Of these investigated samples, sample annealed in O2 ambient possessed the lowest leakage current and the highest electric field (∼6.6 MV/cm) at 10−6 A/cm2 due to the attainment of the lowest interface trap density, total interface trap density, and slow trap density as well as the presence of positive effective oxide charge.

The impact of thermal annealing on the morphology of sputter deposited platinum clusters into anodic aluminum oxide pores

The influence of post deposition annealing (PDA) up to temperatures of TPDA=900°C on the morphology and agglomeration behavior of ambient temperature sputter deposited platinum onto anodic aluminum oxide templates is investigated. Both cluster agglomeration and diffusion processes occur on the surface and on the inner channel walls. When the annealing temperature is less than 400°C, particles are diffusing inside the channels. Around TPDA=400°C, a particle agglomeration process is taking place. A diffusion process is playing an important role and the Pt particles are able to reach a depth of 12μm. The surface morphology exhibits a remarkable change for annealing temperature above 600°C, where Pt is migrating on the outermost surface for forming flat films. When further enhancing TPDA to 900°C, the particles on the surface and in the channels agglomerate together to form separated large flat islands. Moreover, the maximum channel depth where platinum is present is around 12μm.

Improved memory characteristics by NH3-nitrided GdO as charge storage layer for nonvolatile memory applications

Charge-trapping memory capacitor with nitrided gadolinium oxide (GdO) as charge storage layer (CSL) is fabricated, and the influence of post-deposition annealing in NH3 on its memory characteristics is investigated. Transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction are used to analyze the cross-section and interface quality, composition, and crystallinity of the stack gate dielectric, respectively. It is found that nitrogen incorporation can improve the memory window and achieve a good trade-off among the memory properties due to NH3-annealing-induced reasonable distribution profile of a large quantity of deep-level bulk traps created in the nitrided GdO film and reduction of shallow traps near the CSL/SiO2 interface.

Influence of post-deposition annealing on structural, optical and electrical characteristics of NiO/ZnO thin film hetero-junction

ABSTRACTTransparent p-n hetero-junction diodes are fabricated using, p-type NiO and n-type ZnO thin films deposited onto a Pt/Ti/glass substrate utilizing RF sputtering technique. The prepared hetero-junctions are studied for the structural, electrical and optical properties and the effect of post-deposition annealing is investigated through I-V measurements and XRD analysis. The as deposited hetero-junction is found to be giving ohmic behaviour while with post-annealing treatment it result in rectification with a ratio of forward-to-reverse current as high as 15 in the range -1.0 to 1.0 V. Forward threshold and the reverse breakdown voltages are found to be about 0.5 and -2.7 V, respectively. The forward-bias I-V characteristics are dominated by the flow of space-charge-limited current with an optical transmission of above 50 % in the visible region important for the transparent electronic device fabrication.

Influence of post-deposition annealing in oxygen ambient on metal–organic decomposed CeO2 film spin coated on 4H-SiC

Post-deposition annealing (PDA) was performed in oxygen ambient at different temperatures (600, 800, 1,000 and 1,150 °C) onto metal–organic decomposition (MOD) prepared CeO2 film spin coated on n-type 4H-SiC substrate. Effects of PDA onto the physical and electrical characteristics of MOD-derived CeO2 were investigated. Four orientations [(111), (200), (220), and (311)] of CeO2 peaks were revealed by X-ray diffraction analysis in all of the samples with a preferred orientation in (200) direction. However, α-Ce2O3 and cerium silicate (Ce2Si2O7) interfacial layers emerged at 1,150 °C. As annealing temperature increased, grain size of films was increased but microstrains were decreased. Electrical results indicated that negative effective oxide charge and slow trap density were decreased as temperature increased. The lowest interface trap density was perceived by sample annealed at 1,000 °C. However, the highest electric field was obtained by sample annealed at 1,150 °C. Reasons that contributed to this observation were discussed.

Influence of post-deposition annealing on the structural, optical and electrical properties of Li and Mg co-doped ZnO thin films deposited by sol–gel technique

Lithium (Li) and magnesium (Mg) co-doped zinc oxide (ZnO) thin films were deposited by sol–gel method using spin coating technique. The films were deposited on glass substrates and annealed at different temperatures. The effects of annealing temperature on the structural, optical and electrical properties of the deposited films were investigated using X-ray diffraction (XRD), Ultraviolet–Visible absorption spectra (UV–VIS), photoluminescence spectra (PL), X-ray photo electron spectroscopy (XPS) and Hall measurements. XRD patterns indicated that the deposited films had a polycrystalline hexagonal wurtzite structure with preferred (0 0 0 2) orientation. All films were found to exhibit a good transparency in the visible range. Analysis of the absorption edge revealed that the optical band gap energies of the films annealed at different temperatures varies between 3.49 eV and 3.69 eV. Room temperature PL spectra of the deposited films annealed at various temperatures consist of a near band edge emission and visible emission due to the electronic defects, which are related to deep level emissions, such as oxide antisite (O Zn), interstitial zinc (Zn i), interstitial oxygen (O i) and zinc vacancy (V Zn) which are generated during annealing process. The influence of annealing temperature on the chemical state of the dopants in the film was analysed by XPS spectra. Ion beam analysis (Rutherford back scattering) experiments were performed to evaluate the content of Li and Mg in the films. Hall measurements confirmed the p-type nature of the deposited films.

Structural and electrical properties of radio frequency magnetron sputtered tantalum oxide films: Influence of post-deposition annealing

The as-deposited and annealed radio frequency reactive magnetron sputtered tantalum oxide (Ta 2O 5) films were characterized by studying the chemical binding configuration, structural and electrical properties. X-ray photoelectron spectroscopy and X-ray diffraction analysis of the films elucidate that the film annealed at 673 K was stoichiometric with orthorhombic β-phase Ta 2O 5. The dielectric constant values of the tantalum oxide capacitors with the sandwich structure of Al/Ta 2O 5/Si were in the range from 14 to 26 depending on the post-deposition annealing temperature. The leakage current density was <20 nA cm −2 at the gate bias voltage of 0.04 MV/cm for the annealed films. The electrical conduction mechanism observed in the films was Poole–Frenkel.

Annealing-temperature Dependence of Compositional Depth Profiles and Chemical Bonding States of CeOx/LaOx/Si and LaOx/CeOx/Si Structure

We have investigated the influence of post deposition annealing (PDA) on compositional depth profiles and chemical structures of CeOx/LaOx/Si(100) and LaOx/CeOx/Si(100) interfaces by angle-resolved X-ray photoemission spectroscopy. Analyses of Ce 3d and O 1s spectra show that a Ce oxidation state changes from Ce4+ to Ce3+ by PDA in N2 at and above 500{degree sign}C and changes from Ce3+ to Ce4+ by PDA in O2 at 300{degree sign}C. This implies that a Ce oxidation state can be controlled by changing the condition of PDA. The diffusion of Ce and La atom occurs at CeOx/LaOx interface by PDA above 500{degree sign}C.

Influence of post-deposition annealing on the microstructure and properties of Ga2O3:Mn thin films deposited by RF planar magnetron sputtering

Thin films of Ga2O3:Mn have been deposited on silicon (100) substrates without intentional heating by radio frequency (RF) planar magnetron sputtering from a Mn-doped Ga2O3 target in an oxygen-argon mixture atmosphere. Microstructure and properties of the deposited Ga2O3:Mn films were systematically investigated as a function of the post-deposition annealing temperature in the range between 500 °C and 1200 °C. X-ray diffraction (XRD) measurements showed that the as-deposited Ga2O3:Mn films were of an amorphous structure in nature. The Ga2O3:Mn films became crystalline by the post-deposition annealing above 800 °C and the crystallinity of the films was continuously improved up to the annealing temperature of 1200 °C. It was shown that the annealed Ga2O3:Mn films possessed a monoclinic β-Ga2O3 phase having a textured structure with (400) and (−401) crystallographic planes oriented preferentially parallel to the substrate surface. The lattice parameters of the monoclinic β-Ga2O3 phase in the 1200 °C annealed Ga2O3:Mn films were measured to be a = 12.152 A, b = 3.043 A, and c = 5.785 A.

Influence of post-deposition annealing on the structural and optical properties of ZnO thin films prepared by sol–gel and spin-coating method

Thin films of zinc oxide have been deposited onto (0001) sapphire substrate by sol–gel and spin-coating methods. The XRD pattern showed that the crystallinity of the annealed ZnO films had improved in comparison with that of the as-grown films. Photoluminescence spectra revealed a two-line structure, which is identified in terms of UV emission and defect-related emission. The emission intensity was found to be greatly dependent on heat treatment. Host phonons of ZnO and a shift of the E 2 (high) peak from its position have been observed from Raman spectra. The surface morphologies of the film had been improved after annealing was observed from AFM images.

Thin Films of HfO2 for High-k Gate Oxide Applications from Engineered Alkoxide- and Amide-Based MOCVD Precursors

thin films with thickness between 2 and were grown by liquid injection metallorganic chemical vapor deposition, LI-MOCVD, on substrates. Different mononuclear precursors , , and were tested in combination with different solvents. Growth rate, surface morphology, crystal structure, and crystal density of the as-deposited films were analyzed as a function of deposition temperature. The influence of postdeposition annealing on the densification and crystallization was studied. Correlation of the structural properties with the electrical properties of metal insulator semiconductor capacitors with Pt top electrodes is discussed. Fully silicided metal gate stacks are additionally discussed for selected samples.

The influence of post-deposition annealing on thermoelectric properties of Bi–Sb–Te films prepared by sputtering

Bi–Sb–Te thin films were prepared for p-type thermoelectric material in micro Peltier cooling devices. Films with four different compositions were elaborated by co-sputtering of BiSb(1:3) alloy and Te targets. Rapid thermal annealing was carried out for the improvement of thermoelectric properties of the as-grown films under a reducing atmosphere. The effects of the thermal treatment on the characteristic properties of the films were investigated with measurements of the electrical transport properties and Seebeck coefficients. The variation of the charge carrier concentration of a film was found to be dependent on the film's composition and closely related to the thermoelectric properties. The decrease of carrier concentration and the increase of mobility due to the crystallization of the chalcogenide phase resulted in the enhancement of the thermoelectric properties. Maximum values of the Seebeck coefficient (∼178 µV K−1) and power factor (∼1.2 × 10−3 W K−2 m−1) were obtained for a film close to the stoichiometric composition (Bi0.5Sb1.5Te3).

Influence of postdeposition annealing on the structural and optical properties of cosputtered Mn doped ZnO thin films

The influence of postgrowth annealing on the structural and optical properties of rf cosputtered Mn doped ZnO thin films deposited on glass substrate at room temperature has been investigated. All as deposited Zn1−xMnxO films are highly textured, with the c axis of the wurtzite structure along the growth direction. The as grown films are in a state of compressive stress and a reduction in stress with postgrowth annealing treatment are observed. The band gap of Mn doped ZnO films (3.34eV) is slightly larger than the pure ZnO film (3.30eV) and is found to decrease with an increase in annealing temperature for all the samples. The optical dispersion of refractive index with photon energy in Zn1−xMnxO films with varying x and different annealing temperature is studied in the light of single oscillator and Pikhtin-Yas’kov [Sov. Phys. Semicond. 15, 81 (1981)] model, respectively.

Diffusion Barrier Properties of W-C-N Thin Film between La0.67Sr0.33MnO3and Si

Tungsten carbon nitride (W-C-N) thin films were produced by reactive radio frequency (RF) magnetron sputtering of tungsten in Ar-N₂ gas mixture. The effects of the variation of nitrogen partial pressure on the composition, and structural properties of these films as well as the influence of post-deposition annealing have been studied. When La_(0.67)Sr_(0.33)MnO₃ was coated on the W-C-N/Si substrate, coercivity (Hc) and magnetization at room temperature shows 58.73 Oe, and 29.4 emu/cc, respectively. In order to improve the diffusion barrier characteristics, we have studied the impurity behaviors to control the ratios of nitrogen and carbon concentrations.