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Abstract In this work, sputtering route has been pursued for the deposition of amorphous InGaZnO thin films under different oxygen partial pressure ratio (O ppr ). The effect of oxygen partial pressure ratio on the microstructure, optical and electrical properties and chemical bonding states of the sputtering-derived amorphous indium-gallium-zinc oxide (α-IGZO) thin films have been investigated by X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis spectroscopy, and a series of electrical measurements. Measurements based on α-IGZO/SiO 2 thin film transistors (TFTs) have shown that oxygen partial pressure ratio can effectively regulate the carrier concentration, the defect trap density in the bulk channel and the interface between the channel and the gate insulator. The appropriate oxygen partial pressure ratio can reduce interface trap density (N it ) and decrease the off-state current (I off ), which can obviously improve the on/off current ratio (I on /I off ) and the stability of the device. In addition, the appropriate oxygen partial pressure ratio increases the overlap of the ns-orbit of metal ions in the film, which is conducive to improve the electronic transport routes and increase the carrier mobility. As a result, the optimized TFTs performance with oxygen partial pressure ratio of 6.3% has been achieved, including a high saturation mobility ( μ sat ) of 9.9 cm2V-1S−1, a large on/off current ratio of 3.5 × 109, a small subthreshold swing (SS) of 0.29 V/decade, a threshold voltage shift of 4 V under positive bias stress for 7200 s, respectively. A resistor loaded inverter was also constructed on α-IGZO/SiO 2 TFTs and exhibited full swing characteristics with a high gain of 10.3, which is sufficient to drive the next stage component in a logic circuit. All the experimental results have indicated that the sputtering-derived α-IGZO thin films have potential application in large-area all-oxide flexible electronics. Highlights • Sputtering-derived amorphous IGZO films were deposited on Si/SiO 2 substrate. • A resistor loaded inverter coupled with IGZO/SiO 2 TFTs was constructed. • The inverter exhibited full swing characteristics with a high gain of 10.3. [ABSTRACT FROM AUTHOR]

The microstructure, optical and electrical properties of sputtering-derived HfGdO high-k gate dielectric thin films as a function of the Gd doping content have been systematically investigated. X-ray diffraction (XRD) measurements have indicated that Gd doping can form a new stable cubic phase. The optical band gap of the HfGdO gate dielectrics increases gradually from 5.82 to 6.14 eV as the Gd doping concentration increases. The electrical properties, such as permittivity, oxide trapped charge density, border trap charge density and leakage current density of samples, are determined using a semiconductor device analyzer. The formation mechanism of leakage current is also discussed in detail. In addition, the interfacial properties of HfGdO/Si gate satcks were tested to establish the electrical properties. The excellent optoelectronic properties, such as the optical band gap of 5.95 eV, leakage current density of 8.33 × 10 −8 A/cm 2 at a bias voltage of 2 V, oxide trapped charge density of −1.06 × 10 12  cm −2 and a border trap charge density of zero and optimized interfacial properties were observed in the HfGdO thin films with sputtering power of 30 W, indicating that it may become a potential high-k gate dielectric in future complementary metal oxide semiconductor (CMOS) devices. [ABSTRACT FROM AUTHOR]

In this study, Y-doped HfO 2 (HYO) high-k gate dielectric thin films have been deposited on cleaned n-type Si wafers by using co-sputtering technique. Annealing temperature dependent structural, optical, interfacial and electrical properties of HYO have been systemically studied using the x-ray diffraction (XRD), ultraviolet–visible spectroscope (UV–Vis), spectroscopy ellipsometry (SE), x-ray photoelectron spectroscopy (XPS) and electrical measurements. Based on XRD measurements, it can be noted that cubic phase has been detected and remained while doping with yttrium element and annealing at high temperature. Optical analysis by SE indicates that incorporation of Y into HfO 2 can enlarge the band gap and decrease the refraction index of the samples. High temperature annealing leads to the formation of low-k SiO 2 layer and silicate. Electrical measurements have demonstrated that MOS capacitor based on HYO/Si gate stack annealed at 400 °C shows excellent electrical properties, such as high dielectric constant, low oxide charge density border trapped oxide charge density and leakage current density, which can be attributed to the increase in band gap and conduction band offset by Y incorporation. [ABSTRACT FROM AUTHOR]

Annealing temperature dependent microstructure, optical and electrical properties of sol-gel-deposited HfGdO high-k gate dielectric thin films on Si substrates are systematically investigated. X-ray spectroscopy (XPS) analyses have confirmed that the interfacial layer at HfGdO/Si interface is mainly silicate and the component increases with increasing the annealing temperature. Moreover, the band offsets for HfGdO/Si gate stack as a function of annealing temperature also have been determined. As a result, it can be noted that increase in valence band offset (Δ E v ) and reduction in conduction band offset (Δ E c ) have been detected. Electrical characterizations have indicated that higher annealing temperature effectively improves the electrical characteristics, such as the increased effective permittivity ( k ) and the decreased flat band voltage shift (Δ V fb ). However, due to the reduced Δ E c and the appearance of crystallization, increased leakage current density has been observed with the increase in annealing temperature. [ABSTRACT FROM AUTHOR]

In this work, the interface chemistry and the reduction of GaAs surface species by using (NH 4 ) 2 S solution prior to Gd-doped HfO 2 (HGO) thin film deposition and the removal of Ga Oxides and elemental As by rapid thermal annealing (RTA) have been investigated by X-ray photoelectron spectroscopy (XPS). Additionally, the effect of the surface passivation and rapid thermal annealing on the electrical properties of MOS capacitors based on sputtering-derived HGO as gate dielectric on GaAs substrate has been detected by means of capacitance-voltage ( C-V ) and leakage current density-voltage ( J-V ) measurements. Based on electrical analysis, it can be noted that the constantly improvement of electrical properties, such as the decreases of flat band voltage (V fb ), hysteresis (ΔV fb ), oxide charge density (O ox ), border trapped oxide charge density (N bt ) and leakage current density, have been observed. Especially, the dielectric constant of 16.72, flat band voltage V fb of 1.19 V, hysteresis ΔV fb of 0.04 V, leakage current density of 1.54 × 10 −5 A/cm 2 at bias voltage of 1 V, total positive charge density and border trap charge density of 6.09 × 10 12 cm −2 and 2.54 × 10 11 cm −2 , respectively render 600 °C-annealed HGO thin films, potential high-k gate dielectrics in future CMOS devices. [ABSTRACT FROM AUTHOR]

In this work, the band gap, interfacial properties and electrical properties of Gd doped ZrO 2 high-k gate dielectric films deposited by solution method have been systematically investigated. Results have shown that Gd doping can increase band gap energy from 5.65 to 5.92 eV and effectively restrain the formation of low-k SiO x interfacial layer between dielectric and Si substrate. Moreover, the conduction band offset is increased from 2.57 to 3.06 eV by Gd doping, which effectively reduces the leakage current density to 1.8 × 10 −6 A/cm 2 . [ABSTRACT FROM AUTHOR]

HfAlO/Ge gate stack with Al 2 O 3 passivation layer and different Al 2 O 3 concentration in HfAlO layer has been deposited on Ge substrate by atomic layer deposition. Based on measurements from capacitance-voltage and current density-voltage curves, the evolution of the electrical properties of Ge-based MOS capacitors based on HfAlO/Al 2 O 3 /Ge gate stack has been determined as functions of precursor ratio and annealing temperature. It has been found that high annealing temperature and high Al 2 O 3 incorporation in HfAlO films can obtain improved electrical properties such as low hysteresis, low flat-band, low flat-band shift and low interface-state density. However, the oxide-charge density obviously increases with rising the annealing temperature and decreasing Al 2 O 3 incorporation in HfAlO film. By analysis and calculation, it can be noted that the samples annealed at 500 °C holds the lowest leakage current density and the change of the precursor ratio has no apparent effect in 500 °C-annealed Ge MOS capacitor. To investigate current conduction mechanism of Ge MOS capacitors employing HfAlO/Al 2 O 3 gate stacks, current density-voltage measurements have been carried out as functions of annealing temperature and precursor ratio. The involved leakage current conduction mechanisms of the as-deposited and 500 °C-annealed HfAlO/Al 2 O 3 /Ge MOS capacitors for substrate injection also have been discussed in detail. [ABSTRACT FROM AUTHOR]

Effects of nitrogen incorporation on the interfacial chemical bonding states, band alignment, electrical properties and leakage current conduction mechanisms of HfGdO-based metal-oxide-semiconductor (MOS) capacitors has been investigated by UV–Vis transmission spectroscopy, X-ray photoemission spectroscopy (XPS), and electrical measurements. XPS results indicate that incorporation of a moderate amount of nitrogen incorporation into HfGdO gate dielectrics can effectively suppress the formation of low- k GeO 2 and Hf(Gd)-Ge-O interfacial layer at the interfacial region. Meanwhile, reduction in band gap and valence band offset and increase in conduction band offset have been observed after nitrogen incorporation. Electrical measurements based on MOS capacitors have shown that MOS capacitor with HfGdON/Ge stacked gate dielectric with N 2 flow rate of 3 sccm exhibits small gate leakage current (1.08 × 10 −3 A/cm 2 at V g = 1 V), almost disappeared hysteresis, and large dielectric constant (29.2). The involved leakage current conduction mechanisms for MOS capacitor devices with and without nitrogen incorporation also have been discussed in detail. [ABSTRACT FROM AUTHOR]

In current work, effects of rapid thermal annealing on the interface chemical bonding states, band alignment, and electrical properties of atomic-layer-deposition-derived HfAlO/Al 2 O 3 gate stack on Si substrates have been studied by X-ray photoemission spectroscopy (XPS), UV–Vis transmission spectroscopy, and electrical measurements. XPS analyses have shown that HfAlO alloy and mixed silicate (Hf-Al-O-Si) increase after post-deposition annealing process. By means of UV–Vis transmission spectroscopy measurements, reduction in band gap for 400 o C-annealed sample has been observed. Accordingly, reduction in the valence band offset and increase in the conduction band offset have been detected for HfAlO/Al 2 O 3 /Si gate stack annealed at 400 °C. Various current conduction mechanisms, such as Poole-Frenkel emission, Fowler-Nordheim (FN) tunneling, and space-charge-limited (SCL) conduction, have been analyzed. Detailed electrical measurements reveal that current conduct mechanisms is SCL conduction at lower field region and FN tunneling and SCL conduction are dominant conduction mechanism at higher field region. [ABSTRACT FROM AUTHOR]

In this letter, annealing temperature dependence on the structure, band gap energy and electrical properties of TiO 2 doped ZrO 2 gate dielectrics deposited by sol-gel method at low temperature were systemically investigated. The crystalline temperature of TiO 2 doped ZrO 2 is up to 600 °C. The transmittance and band gap value of the ZrTiO x film were about 75% and 4.0 eV, respectively. 300 °C-annealed ZrTiO x MOS capacitor with high dielectric constant of 34.9, a small hysteresis value of 0.004 and low leakage current density of 2.7 × 10 −4 A/cm 2 were obtained. The dominant conduction mechanisms of Al/ZrTiO 4 / n -Si MOS structures were schottky emission and ohmic conduction in the low electric field and direct tunneling in the high electric field. As a result, it can be concluded that sol-gel derived ZrTiO x gate dielectric displays potential application as is a promising candidate in future MOS electronic devices. [ABSTRACT FROM AUTHOR]

Deposition of HfTiO x gate dielectric films on n-type Si and quartz substrates by sol–gel technique has been performed and the optical, electrical characteristics of the as-deposited HfTiO x thin films as a function of baking temperature have been investigated. The components and optical properties of HfTiO x thin films related to baking temperature are investigated by energy dispersive spectrometer (EDS), ultraviolet–visible spectroscopy (UV–Vis), and spectroscopy ellipsometry (SE). By measurement of EDS, the Hf/Ti molar ratio of HfTiO x thin films is calculated to be about 1:1.20 at all baking temperature. The increase in band gap is observed with the increase of baking temperature. Additionally, the electrical properties based on Al/Si/HfTiO x /Al capacitor are analyzed by means of the high frequency capacitance-voltage ( C-V ) and the leakage current density-voltage ( J-V ) characteristics. Results have shown that 200 °C-baked sample demonstrates good electrical performance, including larger dielectric constant of 23.31 and lower leakage current density of 5.12 × 10 −5 A/cm 2 at the gate voltage of 1 V. Additionally, the leakage current conduction mechanisms as functions of baking temperatures are also discussed systematically. [ABSTRACT FROM AUTHOR]

High- k HfO x N y and HfO 2 have been applied to amorphous InGaZnO ( a -IGZO) metal–oxide–semiconductor (MOS) capacitors as high-k gate dielectrics by using radio-frequency sputtering at room temperature. Effects of nitrogen incorporation on the optical band gap, band alignment and electrical properties of HfO x N y /IGZO/Si gate stacks have been systematically investigated by spectroscopic ellipsometry (SE), UV–vis spectroscopy, x-ray photoemission spectroscopy (XPS) and electrical measurements. Experimental results have confirmed the successful incorporation of nitrogen into HfO 2 films and reduction in band gap with the incorporation of nitrogen for HfO x N y thin films. Reduction in valence band offset and increase in conduction band offset have been observed for HfO x N y /IGZO gate stack. Electrical properties measurements for a -IGZO MOS capacitors based on HfO x N y gate dielectrics have indicated that nitrogen incorporation leads to the improved interface quality, increased dielectric constant, reduced hysteresis voltage, and decreased leakage current density. Meanwhile, the leakage current mechanism under gate injection for MOS capacitors based on HfO 2 and HfO x N y high-k gate dielectrics has been investigated systematically. [ABSTRACT FROM AUTHOR]

The effect of oxygen partial pressure on the microstructure, wettability, optical and electrical properties of sputtering-derived HfO 2 thin films has been systematically investigated by using x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscope (AFM), UV–visible spectroscopy (UV–Vis), spectroscopy ellipsometry (SE), and electrical measurements. XRD results have shown that the HfO 2 thin films are all polycrystalline with monoclinic phase. Based on analysis from FTIR, a strong absorption peak centered at 1105 cm −1 has been detected, indicating the formation of the interfacial layer. Reduction in particle size and decrease in root mean square (RMS) roughness of the HfO 2 thin films have been detected by SEM and AFM measurements with the increase in oxygen partial pressure. Meanwhile, the contact angle decreases and the wettability increases with increasing the oxygen partial pressure. Combined with UV–vis and SE, the optical function of HfO 2 thin films as functions of oxygen partial pressure has been determined. By means of electrical measurements, evolution of electrical performance of MOS capacitor based on HfO 2 gate dielectrics related with oxygen partial pressure has been investigated systematically. [ABSTRACT FROM AUTHOR]

High-k gate dielectric HfTiO x thin films have been deposited on Si and quartz substrate by radio frequency (RF) magnetron sputtering. The structural and optical properties of HfTiO x thin films related to deposition power are investigated by X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), and spectroscopic ellipsometry (SE). Results indicate that the as-deposited HfTiO x thin films are amorphous state regardless of the deposition power. The increase of band gap of the samples is observed with the increase of deposition power. Moreover, the increase of the thickness, deposition rate, refractive index (n) and the decrease of the extinction coefficient with the increase of deposition power are also confirmed. Additionally, the electrical properties of films are analyzed by measurement of high frequency capacitance–voltage ( C–V ) and leakage current density-voltage ( J-V ) characteristics. And the leakage current conduction mechanisms are also discussed. [ABSTRACT FROM AUTHOR]

The effect of boron (B) doping on the microstructure, band gap energy and electrical properties of ZrO 2 gate dielectrics deposited by sol–gel method at low temperature were systemically investigated. By means of characterization of spectroscopy ellipsometry and ultraviolet–visible spectroscopy, the thicknesses and optical constants of ZrO 2 gate dielectrics have been determined precisely. The B incorporation dependent electrical properties of ZrO 2 films were determined by capacitance–voltage ( C–V ) and leakage current density–voltage ( J–V ) measurements. The dominant conduction mechanisms of Al/B:ZrO 2 / n -Si MOS structures have been discussed systematically in detail. As a result, the optimized B incorporation content has been obtained to achieve ZrO 2 gate dielectrics with high quality. [ABSTRACT FROM AUTHOR]

Current conduction mechanisms of Hf 1−x Ti x O 2 -gated metal–oxide–semiconductor (MOS) capacitors depending on various post-annealing temperature (PDA) have been investigated. The sample subjected to 400 °C annealing exhibits superior performance with negligible hysteresis memory window shift (ΔV fb = 0.005 V) and lowest gate leakage current density (5.4 × 10 −5 A/cm −2 at V g = 2 V). In addition, evolution of density of interface traps ( D it ), border charger density (N ot ) and oxide charge density (Q ox ) as a function of annealing temperature were investigated in details. Detailed electrical measurements reveal that the dominant current conduction behaviors are Poole–Frankel (P–F) emission in the region of low electric fields and Schottky Emission (SE) in the region of high electric fields for gate injection. For substrate injection, however, is mainly via Ohm's conduction, Schottky emission (SE) conduction mechanism serves in low applied field in the samples, respectively. [ABSTRACT FROM AUTHOR]

The effect of nitrogen on the band offset of sputtering-derived InZnGaO 4 (IGZO)/Si heterostructures has been systematically investigated by x-ray photoelectron spectroscopy (XPS) measurements. Elemental analysis indicates that nitrogen has been successfully incorporated into the IGZO film. By using In 3d 5/2 , In 3d 3/2 and Ga 3d core level (CL) XPS spectra as references, values of valence band offsets (Δ E v ) of have been determined to be 2.56 ± 0.02 and 2.44 ± 0.02 eV for IGZO/Si and IGZO:N/Si heterojunctions, respectively. Using the experimental band gap of 3.59 and 3.50 eV of the IGZO/Si and IGZO:N/Si, the calculated values of conduction band offset (Δ E c ) is 0.09 ± 0.01 and 0.06 ± 0.01 eV, respectively. The results indicate that nitrogen incorporation leads to the reduction in band gap and Δ E v and the slight effect on the Δ E c has also been detected. [ABSTRACT FROM AUTHOR]

Sputtering-derived HfO 2 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 HfO 2 /Si gate stack has been investigated. XPS analyses show that an interfacial layer between HfO 2 and silicon substrate has been found in the post-deposition annealing process. Increase in Hf-silicate layer and reduction in SiO 2 low-k interface layer have been detected. Electrical measurements of MOS capacitor based on Al/HfO 2 /Si gate stacks indicate that annealing HfO 2 sample at 300 °C demonstrated the improved electrical performance. As a result, the leakage current of 3.60 × 10 −5 A/cm 2 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. [ABSTRACT FROM AUTHOR]

Nitrogen content dependent optical constant and electrical properties of sputtering-derived HfTiON gate dielectrics on Si substrate have been investigated. By means of characterization of ultraviolet–visible spectroscopy, reduction in band gap of HfTiON film has been detected with the increase in nitrogen concentration. Electrical measurements of MOS capacitor based on Al/HfTiON/Si gate stacks have indicated that a low interface-state density with almost ignorable frequency dispersion at applied gate voltage of 1 V have been obtained for all samples. With increasing the nitrogen concentration, the improved electrical performance has been observed. For the sample with Ar/N 2 flow ratio of 20/5, rapid thermal annealing (RTA) treatment at 200 °C achieves relatively favorable excellent electrical properties in terms of low gate leakage current density and oxide charge density ( Q ox ). The conduction mechanism for 200 °C-annealed sample has been analyzed systematically. [ABSTRACT FROM AUTHOR]

In current report, X-ray photoelectron spectroscopy has been pursued to obtain the valence band discontinuity (Δ E v ) of sputter deposited HfTiO/InZnGaO 4 (IGZO) heterostructures. A Δ E v value of 0.32 ± 0.1 eV was obtained by using the Ga 2p3/2, Zn 2p3/2, and In 3d5/2 energy levels as references. Taking into consideration the experimental band gaps of 5.35 eV and 3.39 eV for HfTiO and IGZO thin films measured by absorption method, respectively, this would result in a conduction band offset of 1.64 eV in this heterostructure. [ABSTRACT FROM AUTHOR]

The effects of substrate temperature ( T s ) on the electrical and optical properties of amorphous InGaZnO thin films deposited by sputtering have been investigated. As T s increased from RT to 400 °C, all the films remained amorphous, the transmission in the visible region increased from 92.8% to 93.54%, and the band gap decreased from 3.42 eV to 3.31 eV. Based on Cauchy–Urbach model, the optical properties of all samples were analyzed by spectroscope ellipsometry (SE) and increase in refractive index has been detected with the increase in T s . Results of Hall measurement showed that substrate temperature have remarkable influence on the resistivity ( ρ ), carrier concentration ( n ), and carrier mobility ( μ ) of IGZO films. As T s increased from RT to 400 °C, ρ decreased from 46.6 to 0.24 Ω cm, and then increased to 1.11 Ω cm at T s of 400 °C, and n increase from 5.67 × 10 15 to 7.33 × 10 18 cm −3 . Investigation of X-ray photoelectron spectroscopy (XPS) indicated that as T s increased, an O 1 s component representing the oxygen vacancies increased in amount and that the intensity ratio of In/Ga increased but that of Zn/Ga decreased. The analysis suggests that the increase of oxygen vacancies could explain the increase in n and reduction in ρ and that the compositional change could explain the change of E g . [ABSTRACT FROM AUTHOR]

Sputtering-derived amorphous InGaZnO (a-IGZO) thin films were grown on Si and glass substrates in a mixed ambient of Ar and O 2 at fixed 0.5 Pa working pressure. The influence of O 2 /Ar flow ratio on the optical and electrical properties of a-IGZO thin films has been systematically investigated by means of characterization from spectroscopic ellipsometry (SE), X-ray diffraction (XRD), scan electron microscopy (SEM), atomic force microscope (AFM), UV–vis spectroscopy, and electrical measurements. Results have shown that the band gap of the as-deposited IGZO films increases from 3.45 eV to 3.75 eV as the O 2 /Ar flow ratio increases from 0% to 20%. Blue shift in band gap and reduction in reactive index with increasing the O 2 /Ar flow ratio have been detected. Electrical measurements have indicated the increase in resistivity at higher O 2 /Ar gas flow ratio. Related mechanics about the increase in band gap and resistivity have been discussed in detail. [ABSTRACT FROM AUTHOR]

Interfacial thermal stability and band alignment of ALD-derived Al 2 O 3 /HfO 2 /Al 2 O 3 /Ge gate stacks have been investigated by X-ray photoelectron spectroscopy (XPS) and spectroscopy ellipsometry (SE) as a function of annealing temperature. It has been found that reduction in interfacial GeO x component and formation of HfAlO alloy layer have been detected with increasing the annealing temperature from 500 to 700 °C. Combined with analysis from XPS and SE, the increase in conduction band offset and reductions in band gap and valence band offset have been observed. When annealing temperature reaches 700 °C, the valence band offset has been reduced to 0.88 eV, which is smaller than the minimal requirement of Δ E v values for high- k dielectrics and, thus, leads to unacceptably high leakage currents. Therefore, annealing temperature should be carefully controlled to guarantee excellent properties of Al 2 O 3 /HfO 2 /Al 2 O 3 /Ge gate stacks in future Ge-based MOS devices. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sputtering-derived Hf1−xTi x O2 gate dielectrics have been deposited on Si substrates. [•] Increase in crystallization temperature and reduction in Eg have been observed. [•] Formation of silicate layer for 9% TiO2-doped HfO2/Si sample has been detected. [ABSTRACT FROM AUTHOR]

Highlights: [•] Al2O3/HfO2/Al2O3 gate stacks has been deposited on Si substrate by ALD. [•] Interface thermal stability related with annealing temperature has been studied. [•] Phase separation at 700°C and silicate formation at 900°C have been detected. [ABSTRACT FROM AUTHOR]

Abstract: Tin dioxide thin films were prepared successfully by pulsed laser deposition techniques on glass substrates. The thin films were then annealed for 30min from 50°C to 550°C at 50°C intervals. The influence of the annealing temperature on the microstructure and optical properties of SnO2 thin films was investigated using X-ray diffraction, optical transmittance and reflectance measurements. Various optical parameters, such as optical band gas energy, refractive index and optical conductivity were calculated from the optical transmittance and reflectance data recorded in the wavelength range 300–2500nm. We found that the SnO2 thin film annealed at temperatures up to 400°C is a good window material for solar cell application. Our experimental results indicated that SnO2 thin films with the high optical quality could be synthesized by pulsed laser deposition techniques. [Copyright &y& Elsevier]