• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.272-272
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• 2014

SnO thin films, 100 nm in thickness, were deposited on glass substrates by RF magnetron sputtering. A stack structure of $SnO_2/SnO$, where few nanometers of $SnO_2$ were determined on the SnO thin film by X-ray photoelectron spectroscopy. In addition, XPS depth profile analysis of the pristine and heat treated thin films were introduced. The electrical behavior of the as-sputtered films during the annealing was recorded to investigate the working conditions for the SnO sensor. Subsequently, The NH3 sensing properties of the SnO sensor at operating temperature of $50-200^{\circ}C$ were examined, in which the p-type semiconducting sensing properties of the thin film were noted. The sensor shows good sensitivity and repeatability to $NH_3$ vapor. The sensor properties toward several gases like $H_2S$, $CH_4$ and $C_3H_8$ were also introduced. Finally, a sensing mechanism was proposed and discussed.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1939-1943
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• 2003

The precise structural analysis of $SnO_{2}$ thin film, which was prepared by PECVD and thickness 2400 ${\AA}$, was tried to do the structural refinement using X -ray diffraction data. The observed diffraction patterns of $SnO_{2}$ thin film had the strongly preferred orientation effect. WIMV method was used to correct the preferred orientation effect. The final weighted R-factor, $R_{WD}$ was 7.92 %. The lattice parameters, a = b == 4.7366(1) ${\AA}$ and c = 3.1937(1) ${\AA}$, were almost in accordance with ones of $SnO_{2}$ powder.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.13-17
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• 2014

The direct-patternable $SnO_2$ thin film was successfully fabricated by photochemical metal-organic deposition. The composition and chemical bonding state of $SnO_2$ thin film were analyzed by using X-ray photoelectron spectroscopy (XPS) from the surface to the interface with Si substrate. XPS depth profiling analysis allowed the determination of the atomic composition in $SnO_2$ film as a function of depth through the evolution of four elements of C 1s, Si 2p, Sn 3d, and O 1s core level peaks. At the top surface, nearly stoichiometric $SnO_2$ composition (O/Sn ratio is 1.92.) was observed due to surface oxidation but deficiency of oxygen was increased to the interface of patterned $SnO_2/Si$ substrate where the O/Sn ratio was about 1.73~1.75 at the films. This O deficient state of the film may act as an n-type semiconductor and allow $SnO_2$ to be applied as a transparent electrode in optoelectronic applications.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.759-766
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• 1994

Our investigation aimed to reduce the leakage current of $Ta_2O_5$ thin film capacitor by layering SnOz thin film layer under Ta thin film, thereby supplying extra oxygen ions from the $SnO_{2}$ underlayer to enhance the stoichiometry of $Ta_2O_5$ during the oxidation of Ta thin film. Tantalum was evaporated by e-beam or sputtered on p-Si wafers with various deposition temperatures and was oxidized by dry--oxygen at the temperatures between $500^{\circ}C$ and $900^{\circ}C$. Aluminum top and bottom electrodes were formed to make Al/$Ta_2O_5$/p-Si/Al or $Al/Ta_2O_5/SnO_2$p-Si/AI MIS type capacitors. LCR meter and pico-ammeter were used to measure the dielectric constants and leakage currents of the prepared thm film capacitors. XRD, AES and ESCA were employed to confirm the crystallization of the thin f~lm and the compositions of the films. Dielectric constant of $Ta_2O_5$ thin film capacitor with $SnO_{2}$ underlayer was found to be about 200, which is about 10 times higher than that of $Ta_2O_5$ thin film capacitor without $SnO_{2}$ underlayer. In addition, higher oxidation temperatures increased the dielectric constants and reduced the leakage current. Higher deposition temperature generally gave lower leakage current. $Ta_2O_5/SnO_2$ capacitor deposited at $200^{\circ}C$ and oxidized at $800^{\circ}C$ showed significantly lower leakage current, $10^{-7}A/\textrm{cm}^2$ at $4 \times 10^{5}$V/cm, compared to the one without $SnO_{2}$ underlayer. XRD showed that $Ta_2O_5$ thin film was crystallized above $700^{\circ}C$. AES and ESCA showed that initially the $SnO_{2}$, underlayer supplied oxygen ions to oxidize the Ta layer, however, Sn also diffused into the Ta thin film layer to form a new $Ta_xSn_YO_Z$ , ternary oxide layer after all.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.304-308
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• 2012

Transparent thin film transistors (TTFT) were fabricated using the rf magnetron sputtered ZnO-$SnO_2$ films as active layers. A ceramic target whose Zn atomic ratio to Sn is 2:1 was employed for the deposition of ZnO-$SnO_2$ films. To study the post-annealing effects on the properties of TTFT, ZnO-$SnO_2$ films were annealed at $200^{\circ}C$ or $400^{\circ}C$ for 5 min before In deposition for source and drain electrodes. Oxygen was added into chamber during sputtering to raise the resistivity of ZnO-$SnO_2$ films. The effects of oxygen addition on the properties of TTFT were also investigated. 100 nm $Si_3N_4$ film grown on 100 nm $SiO_2$ film was used as gate dielectrics. The mobility, $I_{on}/I_{off}$, interface state density etc. were obtained from the transfer characteristics of ZnO-$SnO_2$ TTFTs.

• Journal of Sensor Science and Technology
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• v.15 no.5
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• pp.309-316
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• 2006

The $SnO_{2}$ thin film sensors were fabricated by a thermal oxidation method. $SnO_{2}$ thin film sensors were treated in $N_{2}$ atmosphere. The sensors with $O_{2}$ treatment after $N_{2}$ treatment showed 70 % sensitivity for 1 ppm $H_{2}S$ gas, which is higher than the sensors with only $O_{2}$ treatment. The Ni metal was evaporated on Sn thin film on the $Al_{2}O_{3}$ substrate. And the sensor was heated to grow the Sn nanowire in the tube furnace with $N_{2}$ atmosphere. Sn nanowire was thermally oxidized in $O_{2}$ environments. The sensitivity of $SnO_{2}$ nanowire sensor was measured at 500 ppb $H_{2}S$ gas. The selectivity of $SnO_{2}$ nanowire sensor compared with thin film and thick film $SnO_{2}$ was measured for $H_{2}S$, CO, and $NH_{3}$ in this study.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.5
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• pp.241-246
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• 2003

The transparent conducting thin film of ATO (antimony-doped tin oxide) was successfully fabricated on$SiO_2$/glass substrate by a sol-gel dip coating method. The crystalline phase of the ATO thin film was identified as SnO$_2$ major phase and the film thickness was about 100 nm/layer at the withdrawal speed of 50 mm/minute. Optical transmittance and electrical resistivity of the 400 nm-thick ATO thin film which was annealed under nitrogen atmosphere were 84% and $5.0\times 10^{-3}\Omega \textrm{cm}$, respectively. It was found that the $SiO_2$ layer inhibited Na ion diffusion and the formation of impurities like $Na_2SnO_3$ or SnO while increasing Sb ion concentration and higher ratio of $Sb^{5+}/Sb^{3+}$in the film. Annealing at nitrogen atmosphere leads to the reduction of $Sn^{4+}$ as well as $Sb^{5+}$ resulting in decrease of the electrical resistivity of the film.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.328-331
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• 2020

In this study, a highly crystalline SnO₂ thin film was formed using a sol-gel process. In addition, a SnO₂ thin-film transistor was successfully fabricated. The fabricated SnO₂ thin-film transistor exhibited conventional n-type semiconductor properties, with a mobility of 0.1 cm² V^-1 s^-1, an on/off current ratio of 1.2 × 10⁵, and a subthreshold swing of 2.69. The formed SnO₂ had a larger bandgap (3.95 eV) owing to the bandgap broadening effect. The fabricated photosensor exhibited a responsivity of 1.4 × 10^-6 Jones, gain of 1.43 × 10⁷, detectivity of 2.75 × 10^-6 cm Hz^1/2 W^-1, and photosensitivity of 4.67 × 10².

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.716-722
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• 1996

Effect of Film thickness on the sensing behavior of thin-film-type ags sensor has been analyzed by deriving an equation form a simple model, and the equation was applied to the sensing behavior of ${SnO}_{2}$ and CuO-${SnO}_{2}$ thin-film sensors. It was revealed, from the equation,that the gas sensing property was closely related to gas diffusivity into the film which was a function of film thickness, reactivity of the gas detected with sensing material, operating temperature, etc. The equation derived was well consistent with the experimental results from ${SnO}_{2}$ and CuO-${SnO}_{2}$ thin-film sensors and explained their different ${H}_{2}S$ sensing behaviors. Finally, a medel was suggested, explainning the effect of gas diffusivity on sensing be havior of oxide semiconductor sensor.

• Korean Journal of Materials Research
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• v.13 no.2
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• pp.111-114
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• 2003

Effects of substrate materials on the microstructure and the sensitivity of $SnO_2$thin film gas sensors have been studied. Various substrates were studied, such as oxidized silicon, sapphire, polished alumina, and unpolished alumina. It was observed that strong correlation exists between the electrical resistance and the CO gas sensitivity of the manufactured sensors and the surface roughness of $SnO_2$thin films, which in turn was related to the surface roughness of the original substrates. X$SnO_2$thin film gas sensor on unpolished alumina with the highest surface roughness showed the highest initial resistance and CO gas sensitivity. The transmission electron microscopy observation indicated that shape and size of the columnar microstructure of the thin films were not critically affected by the type of substrates.