Effect Of Post Deposition Annealing Temperature Research Articles

Effects of post-deposition annealing temperatures in argon ambient on structural, optical, and electrical characteristics of RF magnetron sputtered gallium oxide films

Different post-deposition annealing temperatures were carried out in argon ambient to investigate the corresponding effects onto structural, morphological, optical, and electrical characteristics of RF magnetron sputtered gallium oxide (Ga2O3) films. Cubic phase of γ-Ga2O3 was transformed to mixed phases of cubic and monoclinic phases of β-Ga2O3 as the temperature was increased from 400 to 800 °C before became fully β-Ga2O3 phases at 1000 °C. Oxygen vacancies and oxygen interstitials were formed, generating deep energy levels in band gap of the Ga2O3 films. Findings revealed the acquisition of the highest current density in the Ga2O3 film annealed at 400 °C as a consequence of the highest density (J) of dislocation and oxygen vacancies in the film. Nonetheless, the formation of a thicker interfacial layer and location of oxygen vacancies in the film annealed at 1000 °C have caused minute increase in the J surpassing that of 800 °C at a gate voltage greater than 15 V.

Effects of post‐deposition annealing of cerium oxide passivation layer in nitrogen‐oxygen‐nitrogen ambient

Effects of post-deposition annealing temperature (400°C, 600°C, 800°C and 1000°C) onto metal-organic decomposed cerium oxide (CeO2) precursor spin-coated on n-type Si substrate was carried out in nitrogen-oxygen-nitrogen ambient. The capability of nitrogen to inhibit further oxidation of the Si surface by attaching to the oxygen vacancies sites was reported. Excessive formation of SiO2 interfacial layer however occurred at 1000°C, surpassing the thickness of the CeO2 passivation layer, leaving behind nitrogen dangling bonds that were inefficient in restricting further oxidation of the Si surface, and hence a permanent dielectric breakdown happened at an electric field of 0.98 MV/cm. The CeO2 passivation layer annealed at 800°C broke down at 4.85 MV/cm and possessed relatively low Dit, Qeff, and slow trap density with negligible formation of interfacial layer, which promoted its use as a promising high k passivation layer.

Effects of post-deposition annealing temperature in nitrogen/oxygen/nitrogen ambient on polycrystalline gallium oxide films

Polycrystalline Ga2O3 films were obtained after post-deposition annealing of as-deposited Ga2O3 films via radio frequency magnetron sputtering at different temperatures (400, 600, 800, and 1000 °C) in nitrogen/oxygen/nitrogen ambient. The Ga2O3 films obtained at lower temperatures (400 and 600 °C) demonstrated semiconducting property while the films obtained at higher temperatures (800 and 1000 °C) demonstrated insulating property based upon the leakage current density-voltage characteristics. The semiconducting properties were originated from the presence of oxygen vacancies as well as nitrogen incorporation as the scattering centre in the films, which could serve as the conducting path of electrons, encouraging a higher leakage current. The acquisition of a smaller direct and indirect band gap by these films further supported the fact that electrons would overcome the potential barrier easier. On the other hands, the presence of oxygen vacancies and nitrogen incorporation as well as preferred orientation of film growth accompanied with dislocation affected the leakage current density-voltage characteristics. Detailed investigation in the aspects of structural, morphological, optical, and electrical characteristics of the films was demonstrated.

Effect of post-deposition annealing temperature on the charge carrier mobility and morphology of DPPDTT based organic field effect transistors

There is a considerable research interest in enhancing the charge carrier mobility of polymer-based organic field effect transistors (OFETs) through processing techniques. Herein, we investigate the effect of post-deposition annealing temperature on morphology and mobility of solution processible polymer Poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)], (DPPDTT) based OFETs. The resulting change in the grain size is proportional to the mobility data. At temperatures higher than 100 °C, grain size decreased with obvious desorption due to low Van der Waals forces in the polymer. Our results will hence contribute towards understanding the annealing mechanism in polymers to optimize the performance of DPPDTT based devices.

Investigation of the Influences of Post-Thermal Annealing on Physical Properties of TiO2 Thin Films Deposited by RF Sputtering

For this study, titanium dioxide (TiO2) thin films were deposited on glass substrates at room temperature by the RF magnetron sputtering technique. The preparation parameters that offer better control and reproducibility of film fabrication were first optimized. Then, the effects of post-deposition annealing temperature at 350, 450, and 550°C on the microstructure, surface morphology, and optical properties of the prepared films were investigated using X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV–Visible (UV–Vis) spectrophotometry. Interestingly, XRD analysis shows that as-deposited and annealed TiO2 film possess anatase crystal structure only with a preferential orientation along the (101) plane. The intensity of the (101) diffraction peak and crystallite size are found to increase with increasing annealing temperature, which indicates an improvement in the crystallinity of the films. Raman spectra confirm that all samples possess anatase phase and the crystallinity is enhanced with increasing thermal annealing. From the analysis of SEM and AFM images, it is revealed that the heat treatment significantly affects the morphology, grain size, and surface roughness of the TiO2 films. The UV–Vis spectroscopy analysis shows that as-deposited TiO2 thin film is highly transparent in the visible region with an average transmittance about 84%, whereas the transmission decreases slightly with an increase in annealing temperature. Moreover, the optical band gap energy shows a red shift with increasing the annealing temperature.

Effects of Post-Deposition Annealing Temperatures on the Composition of Interfacial Layer at Germanium (Ge)/Aluminium Oxide (Al2O3)

The understanding of chemical bonding structure of high k dielectrics/Germanium (Ge) interface is upmost importance in order to form a good quality dielectric/Ge interface in fabricating Ge metal oxide semiconductor field effect transistor (MOSFETs). In addition, there is still no detail explanation on the interfacial growth of dielectrics/Ge under the influenced of different temperature of post deposition anneal. In current work, the effects of post deposition anneal (PDA) temperature between 400°C and 600°C on the chemical composition of interfacial layer between Ge and Al2O3 were examined by X-ray photoelectron spectroscopy (XPS). Investigation on thermal stability and structural characteristics for gate structure of Al2O3 dielectric grown on Ge by RF sputtering was done by analyzing X-ray photoelectron spectroscopy (XPS) spectra. It is observed that the oxygen deficient region in interfacial layer (IL) is enhanced rather than fully oxidized Al2O3 with increased PDA temperatures. These undesired phenomena caused shrinkage of IL at Ge/Al2O3 interface at higher temperature of 600°C.

Control of crystal structure, morphology and optical properties of ceria films by post deposition annealing treatments

In this paper, the effects of post-deposition annealing temperature and atmosphere on the properties of pulsed DC magnetron sputtered ceria (CeO2) thin films, including crystalline structure, grain size and shape and optical properties were investigated. Experimental results, obtained from X-ray diffraction (XRD), showed that the prepared films crystallised predominantly in the CeO2 cubic fluorite structure, although evidence of Ce2O3 was also seen and this was quantified by a Rietveld refinement. The anneal temperature and oxygen content of the Ar/O2 annealing atmosphere both played important roles on the size and shape of the nanocrystals as determined by atomic force microscopy (AFM). The average grain size (determined by an AFM) as well as the out of plane coherence length (obtained from XRD) varied with increasing oxygen flow rate (OFR) in the annealing chamber. In addition, the shape of the grains seen in the AFM studies transformed from circular to triangular as the OFR was raised from 20sccm to 30sccm during an 800°C thermal anneal. X-ray photoelectron spectroscopy was used to measure near-surface oxidation states of the thin-films with varying OFR in the annealing chamber. The bandgap energies were estimated from the ultra-violet and visible absorption spectra and low-temperature photoluminescence. An extracted bandgap value of 3.04eV was determined for as-deposited CeO2 films and this value increased with increasing annealing temperatures. However, no difference was observed in bandgap energies with variation of annealing atmosphere.

Effects of annealing temperature on optical, morphological, and electrical characteristics of polyfluorene-derivative thin films on ITO glass substrate.

The effects of postdeposition annealing temperature (125°C-200°C) toward optical, morphological, and electrical characteristics of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-phenylene)] end capped with dimethylphenyl group deposited on indium tin oxide glass substrates were investigated. Green and red-infrared photoluminescence emissions, originating from П-conjugation aggregates and keto-type defects did not attenuate the intensity of the blue emission peak. This suggested that the aggregates and defects might serve as local traps for radiative recombination. In samples annealed at 125°C-175°C, a decreasing optical energy gap (E(g)) that decreased barrier height as well as an increasing amount of traps have increased current conduction via thermionic emission and trap-assisted tunneling. Nonetheless, an acquisition of the largest E(g) and amount of traps testified that thermionic emission was dominating current conduction, surpassing trap-assisted tunneling in samples annealed at 200°C.

Microstructure, optical and electrical properties of solution-derived peroxo-zirconium oxide gate dielectrics for CMOS application

Solution-processed high-k gate dielectrics for metal-oxide-semiconductor (MOS) capacitor have been widely investigated with the objective of achieving high performance field effect transistors (FETs) for next-generation microelectronic device. In current work, the effect of postdeposition annealing temperature on the microstructure, optical and electrical properties of peroxo-zirconium oxide (ZrO2) gate dielectrics fabricated by a simple spin-coating method has been studied systemically. By means of characterization of spectroscopy ellipsometry and ultraviolet–visible spectroscopy, the thicknesses and optical constants of ZrO2 gate dielectrics have been determined precisely. The annealing temperature dependent electrical properties of ZrO2 films were determined by capacitance–voltage (C–V) and leakage current density–voltage (J–V) measurements. Based on the implementation as gate insulator, the solution-processed ZrO2-based MOS capacitor showed good and stable performances during annealing at 700°C. As a result, the dominant leakage conduction mechanism for optimized 700°C-annealed sample has been discussed in detail. Our results show the possibility of the solution-processed ZrO2 dielectric layer as a gate insulator for application in MOSFETs.

Annealing temperature modulated interfacial chemistry and electrical characteristics of sputtering-derived HfO2/Si gate stack

Sputtering-derived HfO2 high-k gate dielectric thin films have been deposited on Si substrate by means of high vacuum physics vapor deposition method. Via characterization from x-ray photoelectron spectroscopy (XPS) and electrical measurements, the effect of post-deposition annealing temperature on the interfacial and electrical properties of HfO2/Si gate stack has been investigated. XPS analyses show that an interfacial layer between HfO2 and silicon substrate has been found in the post-deposition annealing process. Increase in Hf-silicate layer and reduction in SiO2 low-k interface layer have been detected. Electrical measurements of MOS capacitor based on Al/HfO2/Si gate stacks indicate that annealing HfO2 sample at 300 °C demonstrated the improved electrical performance. As a result, the leakage current of 3.60 × 10−5 A/cm2 at applied substrate voltage of 2 V, which is much lower than those samples annealed at other temperature, has been obtained. The leakage current mechanism for different annealing temperature has been discussed systematically.

Influence of post-deposition annealing time on oxygen gas sensing behaviour of Al/La0·50Ce0·50O1·75/Si metal-oxide-semiconductor capacitor

Effects of post-deposition annealing temperature (400–1000°C) towards sensing performance of a Si-based metal-oxide-semiconductor gas sensor in regard to oxygen gas have been investigated by utilising La0·50Ce0·50O1·75 as the catalytic oxide. The highest sensitivity and best recovery have been obtained by the sensor with its oxide post-deposition annealed at 1000°C. This was associated with the presence of more oxygen vacancies in the oxide that have served as adsorption sites for the oxygen gas molecules. The gas molecules would be adsorbed and dissociated to active oxygen species, which would cause a shift in the current–gate voltage curve to lower current level during gas flow. Response time and recovery time of the sensor were calculated, discussed and explained based on the presence of oxygen vacancies in the oxide.

Plastic Compatible Sputtered ${\hbox{Ta}}_{2}{\hbox{O}}_{5}$ Sensitive Layer for Oxide Semiconductor TFT Sensors

The effect of post-deposition annealing temperature on the pH sensitivity of room temperature RF sputtered Ta <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> was investigated. Structural and morphological features of these films were analyzed before and after annealing at various temperatures. The deposited films are amorphous up to 600 °C and crystallize at 700 °C in an orthorhombic phase. Electrolyte-insulator-semiconductor (EIS) field effect based sensors with an amorphous Ta2O5 sensing layer showed pH sensitivity above 50 mV/pH. For sensors annealed above 200 °C pH sensitivity decreased with increasing temperature. Stabilized sensor response and maximum pH sensitivity was achieved after low temperature annealing at 200 °C, which is compatible with the use of polymeric substrates and application as sensitive layer in oxides TFT-based sensors.

Thermal stability of pulsed laser deposited iridium oxide thin films at low oxygen atmosphere

Iridium oxide (IrO2) thin films have been regarded as a leading candidate for bottom electrode and diffusion barrier of ferroelectric capacitors, some process related issues need to be considered before integrating ferroelectric capacitors into memory cells. This paper presents the thermal stability of pulsed laser deposited IrO2 thin films at low oxygen atmosphere. Emphasis was given on the effect of post-deposition annealing temperature at different oxygen pressure (PO2) on the crystal structure, surface morphology, electrical resistivity, carrier concentration and mobility of IrO2 thin films. The results showed that the thermal stability of IrO2 thin films was strongly dependent on the oxygen pressure and annealing temperature. IrO2 thin films can stably exist below 923K at PO2=1Pa, which had a higher stability than the previous reported results. The surface morphology of IrO2 thin films depended on PO2 and annealing temperature, showing a flat and uniform surface for the annealed films. Electrical properties were found to be sensitive to both the annealing temperature and oxygen pressure. The room-temperature resistivity of IrO2 thin films with a value of 49–58μΩcm increased with annealing temperature at PO2=1Pa. The thermal stability of IrO2 thin films as a function of oxygen pressure and annealing temperature was almost consistent with thermodynamic calculation.

Effects of post-deposition annealing temperature on metal-organic decomposed lanthanum cerium oxide film as metal reactive oxide layer on 4H-SiC

Investigation of metal-organic decomposed LaxCeyOz film was performed on n-type 4H-SiC substrate by varying post-deposition annealing (PDA) temperature from 400 to 1000 °C. The LaxCeyOz acting as a metal reactive oxide layer was demonstrated, explained, and justified via X-ray photoelectron spectroscopy (XPS) through its effect in performing catalytic oxidation of the substrate with temperature as low as 400 °C and the removal of excess carbon, originated from the substrate itself, accumulated at the oxide/4H-SiC interface via formation of CO. Williamson–Hall approach has revealed an increment in crystallite size for LaxCeyOz with decreasing microstrains as PDA temperature increased. High resolution transmission electron microscopy showed the formation of a distinct amorphous interfacial layer in between the bulk oxide and SiC substrate. XPS analysis proved that the bulk oxide with a mixture of amorphous and crystalline regions was comprised of an intermixing of La, Ce, O, C, and La, Ce, O, Si, C elements while interfacial layer consisted of La, Ce, O, Si, and C elements.

Effect of post-deposition annealing temperature on RF-sputtered HfO2 thin film for advanced CMOS technology

Structural and electrical properties of HfO2 gate-dielectric metal-oxide-semiconductor (MOS) capacitors deposited by sputtering are investigated. The HfO2 high-k thin films have been deposited on p-type <100> silicon wafer using RF-Magnetron sputtering technique. The Ellipsometric, FTIR and AFM characterizations have been done. The thickness of the as deposited film is measured to be 35.38 nm. Post deposition annealing in N2 ambient is carried out at 350, 550, 750 °C. The chemical bonding and surface morphology of the film is verified using FTIR and AFM respectively. The structural characterization confirmed that the thin film was free of physical defects and root mean square surface roughness decreased as the annealing temperature increased. The smooth surface HfO2 thin films were used for Al/HfO2/p-Si MOS structures fabrication. The fabricated Al/HfO2/p-Si structure had been used for extracting electrical properties such as dielectric constant, EOT, interface trap density and leakage current density through capacitance voltage and current voltage measurements. The interface state density extracted from the G–V measurement using Hill Coleman method. Sample annealed at 750 °C showed the lowest interface trap density (3.48 × 1011 eV−1 cm−2), effective oxide charge (1.33 × 1012 cm−2) and low leakage current density (3.39 × 10−9 A cm−2) at 1.5 V.

Systematic investigation of the annealing temperature and composition effects on the dielectric properties of sol–gel BaxSr1−xTiO3 thin films

Abstract In this work, Ba x Sr 1− x TiO 3 sol–gel thin films ( x = 0.7, 0.5 and 0.3) deposited on Pt/Si substrate and post-annealed at different temperatures have been investigated. A systematic study of the structure, microstructure and dielectric properties has been achieved for each composition. To our knowledge, for the first time, a systematic effect of post-deposition annealing temperature and composition is reported. For each Ba/Sr ratio, higher annealing temperature leads to crystallinity improvement and to grain growth. A shift of the ferroelectric to paraelectric transition toward the bulk Curie temperature with the increase of the annealing temperature is shown. These results are correlated with the increase of the permittivity, tunability and dielectric losses measured on MIM capacitors at low frequency. Moreover, the high frequency results, between 800 MHz and 30 GHz, are in very good agreement with low frequency measurements, and show a huge tunability up to 80% under 600 kV/cm.

Metal-oxide-semiconductor characteristics of lanthanum cerium oxide film on Si

Metal-organic decomposed lanthanum cerium oxide (La x Ce y O z ) film had been spin-coated on n-type Si substrate. Effects of post-deposition annealing temperature and time on the metal-oxide-semiconductor (MOS) properties of the film were studied. As temperature increased from 400 to 1000°C for 15 minutes dwell time, La x Ce y O z demonstrated a decrease in interface trap density (D it) and total interface trap density (D total), which were related to the formation of SiO x /silicates interfacial layer (IL). The lowest leakage current density and highest dielectric breakdown voltage (V B) was obtained in 1000°C-annealed sample. When longer annealing times (30–120 minutes) were studied on the 1000°C-annealed sample, the sample annealed at 1000°C for 120 min showed the best MOS characteristics with V B of 30 V. Reasons contributing to such observation were discussed.

Effects of Post-Deposition Annealing Temperature on Band Alignment and Electrical Characteristics of Lanthanum Cerium Oxide on 4H-SiC

ABSTRACTInvestigation of lanthanum cerium oxide as a gate oxide on 4H-SiC was performed by varying post-deposition annealing temperature from 400 to 1000°C. Energy band alignment and band gap of bulk oxide and interfacial layer (IL) with respect to SiC were extracted using X-ray photoelectron microscopy. Two band alignment structures were proposed and the change of band alignment was affected by the changes in chemical composition in bulk oxide and in IL that may induce lattice strains and dipoles. A conduction band offset of IL/SiC was 0.97 eV for sample annealed at 1000°C, which was comparable to the value extracted from Fowler-Nordheim model. The acquisition of sufficient conduction band offset, coupled with the lowest slow trap density, effective oxide charges, interface trap density, as well as total interface trap density, yielded the lowest leakage current density for this sample.

Effects of Post-deposition Annealing Temperature on the Structure and Photoluminescence of Zinc Germanate Thin Films Doped with Manganese

Effects of Post-deposition Annealing Temperature on the Structure and Photoluminescence of Zinc Germanate Thin Films Doped with Manganese

Effects of post-deposition annealing temperature and ambient on RF magnetron sputtered Sm2O3 gate on n-type silicon substrate

Samarium oxide (Sm2O3) thin films with thicknesses in the range of 15–30 nm are deposited on n-type silicon (100) substrate via radio frequency magnetron sputtering. Effects of post-deposition annealing ambient [argon and forming gas (FG) (90% N2 + 10% H2)] and temperatures (500, 600, 700, and 800 °C) on the structural and electrical properties of deposited films are investigated and reported. X-ray diffraction revealed that all of the annealed samples possessed polycrystalline structure with C-type cubic phase. Atomic force microscope results indicated root-mean-square surface roughness of the oxide film being annealed in argon ambient are lower than that of FG annealed samples, but they are comparable at the annealing temperature of 700 °C (Argon—0.378 nm, FG—0.395 nm). High frequency capacitance–voltage measurements are carried out to determine effective oxide charge, dielectric constant and semiconductor-oxide interface trap density of the annealed oxide films. Sm2O3 thin films annealed in FG have smaller amount of effective oxide charge and semiconductor-oxide interface trap density than those oxide films annealed in argon. Current–voltage measurements are conducted to obtain barrier heights of the annealed oxide films during Fowler–Nordheim tunneling.