• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.265.2-265.2
• /
• 2016

Oxide thin film transistors (TFTs) have attracted considerable interest for gate diver and pixel switching devices of the active matrix (AM) liquid crystal display (LCD) and organic light emitting diode (OLED) display because of their high field effect mobility, transparency in visible light region, and low temperature processing below $300^{\circ}C$. Recently, oxide TFTs with polycrystalline In-Ga-O(IGO) channel layer reported by Ebata. et. al. showed a amazing field effect mobility of $39.1cm^2/Vs$. The reason having high field effect mobility of IGO TFTs is because $In_2O_3$ has a bixbyite structure in which linear chains of edge sharing InO6 octahedral are isotropic. In this work, we investigated the characteristics and the effects of oxygen partial pressure significantly changed the IGO thin-films and IGO TFTs transfer characteristics. IGO thin-film were fabricated by rf-magnetron sputtering with different oxygen partial pressure ($O_2/(Ar+O_2)$, $Po_2$)ratios. IGO thin film Varies depending on the oxygen partial pressure of 0.1%, 1%, 3%, 5%, 10% have been some significant changes in the electrical characteristics. Also the IGO TFTs VTH value conspicuously shifted in the positive direction, from -8 to 11V as the $Po_2$ increased from 1% to 10%. At $Po_2$ was 5%, IGO TFTs showed a high drain current on/off ratio of ${\sim}10^8$, a field-effect mobility of $84cm^2/Vs$, a threshold voltage of 1.5V, and a subthreshold slpe(SS) of 0.2V/decade from log(IDS) vs VGS.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.355-355
• /
• 2010

The epitaxial growth of MgO film on Fe(001) has been investigated by scanning tunneling microscopy (STM). After confirming the clean Fe(001)-c($2{\times}2$) substrate by STM, Mg was deposited at room temperature (RT) under $O_2$ partial pressure of $10^{-7}\;Torr$. The MgO was grown as clusters, not as an epilayer even after postannealing at $400^{\circ}C$, as shown in Figure (a). On the contrary, when Mg was deposited on Fe(001)-c($2{\times}2$) at RT and post-oxidized through exposing $O_2$ at partial pressure $10^{-7}\;Torr$, the thin-layered film with some clusters was formed. Extended-annealing at $400^{\circ}C$ reduced the cluster density, and finally the single and epitaxial MgO-c($2{\times}2$) film was formed on Fe(001)-c($2{\times}2$) as shown in Figure (b). This ultrathin MgO film formed on Fe is expected to be applied to many technological applications, such as catalysis, microelectronics, and magnetic devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.209-209
• /
• 2009

Fabrication of p-type ZnO has already proven difficult and usually inconsistent despite numerous worldwide efforts. Many research groups studied electrical and optical properties P, Li, As, N single doped ZnO thin film. In P-doped ZnO thin film, the reproducibility of p-type conduction with $P_2O_5$ as a dopant source was shown to be relatively poor. In this study, we made P single doped and Li & P co-doped ZnO target. To investigate electrical and optical properties of P single doped and Li & P co-doped ZnO thin film using $P_2O_5$ and $Li_3PO_4$ dopant source respectively was deposited by PLD. The growth temperature was changed 500, $700^{\circ}C$ and various oxygen partial pressure and post-annealing conditions was changed temperature, different gas ambient($O_2,N_2$). We investigate that how to change electrical and optical properties as function of growth temperature, oxygen partial pressure and post-annealing(RTA).

• Journal of Sensor Science and Technology
• /
• v.13 no.4
• /
• pp.298-302
• /
• 2004

Thick films of $LaNiO_{3}$ having perovskite structure impregnated with indium and bismuth oxides have been used as sensing material for acetonitrile ($CH_{3}CN$) gas. The sensor response for $CH_{3}CN$ is quite good with an excellent recovery for partial pressure from 3 ppm to 20 ppm between 200 and $250^{\circ}C$. $LaNiO_{3}$ alone has exhibited low response, but after impregnation of $In_{2}O_{3}$ and $Bi_{2}O_{3}$ have given increased sensitivity even with 3 ppm partial pressure of $CH_{3}CN$ at $200^{\circ}C$. It is assumed that $CH_{3}CN$ is undergoing oxidation reaction on surface of the film.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.122-123
• /
• 2006

Tin oxide nanoparticles (n-SnO and $n-SnO_2$) were synthesized by the inert gas condensation (IGC) method under dynamic gas flow of oxygen and argon at various conditions. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) method were used to analysis the size, shape and crystal structure of the produced powders. The synthesized particles were mostly amorphous and their size increased with increasing the partial pressure of oxygen in the processing chamber. The particles also became broader in size when higher oxygen pressures were applied. Low temperature annealing at $320^{\circ}C$ in air resulted to crystallization of the amorphous n-SnO particles to $SnO_2$.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2005.04a
• /
• pp.57-57
• /
• 2005

• Korean Journal of Materials Research
• /
• v.9 no.1
• /
• pp.57-64
• /
• 1999

The electrical conductivity of TiO$_2$ doped with 0.05~1.5mol% WO$_3$ was measured in the oxygen partial pressure range of 10\ulcorner~10\ulcorner atm and temperature range of 1100~130$0^{\circ}C$ to investigate the defect types and the electrical properties. The grain size and density were increased as the liquid phase was formed by the doped WO$_3$. The secondary phase and WO$_3$peaks at the sample doped up to 4.0 mol% were not detected from the XRD results. The data(log$\sigma$/logPo$_2$) over 110$0^{\circ}C$ were divided into the four regions. From these experimental results, we proposed the following defect regions. 1) Magneli phase(extended defect), 2) Reduced rutile region which is similar to the behavior of undoped rutile, 3) Nearly stoichiometric Ti\ulcornerW\ulcornerO$_2$region in which extra charge of W\ulcorner cation is expected to be compensated by an electron, 4) Overstoichiometric Ti\ulcornerW\ulcornerO\ulcorner region which is a metal deficiency not to be observed in pure TiO$_2$. The electrical conductivity of w-doped TiO$_2$ was influenced by the measuring temperature, oxygen partial pressure, and the dopig content.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.8-8
• /
• 2009

Thin-film transistors (TFTs) were fabricated using amorphous indium gallium zinc oxide (a-IGZO) channels by rf-magnetron sputtering at room temperature. We have studied the effect of oxygen partial pressure on the threshold voltage($V_{th}$) of a-IGZO TFTs. Interestingly, the $V_{th}$ value of the oxide TFTs are slightly shifted in the positive direction due to increasing $O_2$ ratio from 1.2 to 1.8%. The device performance is significantly affected by varying $O_2$ ratio, which is closely related with oxygen vacancies provide the needed free carriers for electrical conduction.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.153-156
• /
• 2003

The multi-layer oxide buffer layer for the coated conductor was deposited on biaxially textured Ni substrates using pulsed laser deposition. Oxygen partial pressure, 4％$H_2$/Ar partial pressure, and deposition temperature were deposition variables investigated to find the optimum deposition conditions. $Y_2$O$_3$seed layer was deposited epitaxially on metal substrate. The full buffer architecture of $Y_2$O$_3$/YSZ/CeO$_2$was successfully prepared on metal substrate.

• Journal of the Korean Ceramic Society
• /
• v.37 no.2
• /
• pp.168-173
• /
• 2000

YMnO3 thin films were prepared on Pt/Ti/SiO2/Si substrate by chemical solution deposition method. The films were crystallized by heat-treatment at 85$0^{\circ}C$ for 1 hour. Effects of an annealing atmosphere(O2, Ar, vacuum) on the crystallization behavior and electridcal properties were investigated. YMnO3 thin films annealed under Ar atmosphere showed a superior crystallinity and a very strong c-aix preferred-orientation which was a polar axis. Leakage current density of the films decreased with lowering oxygen partial pressure of the annealing atmosphere. C-V and P-E ferroelectric hysteresis were observed only in the thin film heat-treated under Ar atmosphere.In order to prepare YMnO3 thin films having both low leakage current and ferroelectricity, the annealing atmsphere should be kept under a proper oxygen partial pressure which was about 1 Pa in this work. Leakage current density at 1 volt, dielectric constant($\varepsilon$r), remanent polarization(Pr), and coercive field(Ec) were 1.7$\times$10-8 A/$\textrm{cm}^2$, 25, 1.08$\mu$C/$\textrm{cm}^2$, and 100 kV/cm, respectively.