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Aluminum nitride (AlN) has been attracting much attention since it has a wide direct transition band gap of 6.3 eV and it is applicable for UV-LEDs. The AlN films have been deposited by chemical vapor deposition (CVD) and atomic layer deposition (ALD). These conventional processes were performed at a temperature of 300 °C and higher. To apply the AlN coating on flexible films, the low temperature deposition process has been demanded. To demonstrate the AlN deposition at RT, an RT-ALD of AlN using trimethylaluminum (TMA) as an Al precursor and plasma-excited ammonia are studied based on study on multiple internal reflection infrared spectroscopy (MIR-IRAS). An n-type Si substrate was used as a prism for MIR-IRAS. The size of prism was 10×45 mm2 and its resistivity was 1000 Ωcm. 45° bevels on each of the short edges were formed. The prism was set in a reaction chamber for the ALD. If the IR spectra before and after the processes are defined as Ir and I0, respectively, we can calculate the absorbance (Abs) from the equation, Abs = log10(Ir/I0). TMA was used as the Al precursor. In the nitridation step, ammonia and argon was mixed with a volume ratio of 7:3, followed by being excited through a quartz tube with an RF power of 250 W and a frequency of 13.56 MHz. The flow rate of the mixed gas was 10 sccm. Ammonia molecules in the mixture were dissociated to NH radicals and some fragments. Plasma excited ammonia was provided in the chamber. We observed the surface reaction to confirm TMA adsorption and examine if the plasma-excited ammonia generated nitride on the TMA adsorbed surfaces. Fig. 1 shows IR spectra were obtained from a TMA adsorbed surface with exposures from 1000 to 400000 L at RT. Peaks at 2933, 2894, and 2829 cm-1 correspond to C-H vibrations in TMA. The positive peak indicates that the TMA was adsorbed on the surface at RT. Fig. 2 shows IR spectra measured from plasma excited ammonia treated TMA saturated surface. Negative peaks at 2933, 2894, and 2829 cm-1 suggests that the nitride was generated there at RT. We also confirmed the presence of AlN on the prism by an Al 2p peak at 73.3 eV and a N 1s peak at 398.1 eV by X-ray photoelectron spectroscopy. These suggests that it is possible to deposit AlN at RT. Figure 1

A room-temperature atomic layer deposition (RT-ALD) of aluminum silicate for molecule sorption is developed using trimethylaluminum (TMA) and trismethylaminosilane (TDMAS) using a plasma excited humidified argon. The aluminum-silicate is a main material of zeolites that is used for cation sorption. If we achieved the aluminum silicate deposition on flexible films, we could expect the film used as a regenerable ion exchange filter. The schematic of ALD system is shown in Fig.1. TMA and TDMAS were introduced with mass flow controllers. A remote plasma system generating excited humidified argon was installed to the ALD chamber. The source gas for the oxidizing gas is a mixture of water vapor and argon. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56 MHz and a RF power of 100 W. For the deposition, we repeated the cycle of TDMAS and TMA saturation and oxidizing gas treatment at RT. To control the aluminum to Si atomic ratio in the aluminum silicate, we adjusted the initial exposure of TDMAS. To confirm the Na sorption ability of the aluminum silicate film deposited by the present technology, we immersed the aluminum silicate coated Si sample in a 100 mM NaCl solution for 3h. The dried sample was evaluated by X-ray photoelectron spectroscopy. As shown in Fig. 2, the enhanced Na adsorption is confirmed. In the conference, we discuss the mechanism of Na sorption on the RT deposited aluminum silicate. Acknowledgements This work was partly supported by JSPS KAKENHI Grant Numbers 15H03536. It was also partly supported by JST-CREST Grant Number JPMJCR14F3, Japan. Figure 1

Core-shell nanoparticles consist of core materials coated with different kinds of films, where new functional material properties are expected by the combination of core and shell materials. In our laboratory, we have been developing the Au-core-oxide-semiconductor shell particles which must be used for the electron channel material. By using the metal core, we can form the particle chain between two adjacent electrodes by using an electrostatic force where the shell material works as a semiconductor channel. We also expect the nanoparticle chain can be formed at a two-dimensional space in a lipid bilayer that could be used for the bio sensors and field effect sensors. We report on the room temperature atomic layer deposition producing the core-shell particles and the related experiments in the presentation.

A room-temperature atomic layer deposition (RT-ALD) of Al2O3 as an anticorrosion coating for metal surfaces was developed using trimethylaluminum (TMA) and a plasma excited humidified argon. The schematic of ALD system is shown in Fig.1. TMA as the aluminum precursor was introduced with a mass flow controller. A remote plasma system generating excited humidified argon was installed to the ALD chamber. The source gas for the oxidizing gas is a mixture of water vapor and argon. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56 MHz and a RF power of 100 W. For the Al2O3 deposition, we repeated the cycle of TMA saturation and oxidizing gas treatment at RT. The TMA exposure was set at 5.86×10-3 Torr×40 sec. The saturation of TMA on the hydroxylated surface was confirmed by the IR absorption spectroscopy. The plasma excited oxidizing gas was injected for 2 min. As a result, we show the anticorrosion test of ALD coated metal in a HCl solution. We used SUS430 plates with a size of 20×50×0.5 mm3 as the sample. In this test, we used a not-attenuated HCl solution with a concentration of 35 %. All the samples were immersed in the HCl solution for a certain amount of minutes at room temperature and we observed its surface coloring. Fig.2 shows a picture of the tested samples. The not-treated SUS430 sample clearly exhibits a white stain by the HCl corrosion. On the other hand, the Al2O3 coated sample maintained a mirror surface, which indicates that the RT-ALD coated film works as the anti-corrosion film against the acid solution. In the conference, we discuss the applicability of the RT-ALD to the anticorrosion coating for metal components. Acknowledgements This work was partly supported by JST-CREST, JSPS KAKENHI Grant Numbers 15H03536 and 15K13299. Figure 1

Tin oxide (SnO2) is an oxide semiconductor material with an excellent optical transparency, where it is used as transparent conducting films. It is also used as a channel material for gas sensors. Recently atomic layer deposition (ALD) of SnO2 has been studied intensively since ALD allows the conformal deposition of the oxide film with an atomic level precision. However, the high process temperature in excess of 100 °C in the conventional SnO2 ALD is a major problem for its application for flexible electronics. We developed a room temperature deposition technique with a precursor of tetramethyl tin (Sn(CH3)4, TMT) and plasma excited humidified argon. The surface reaction of the precursor adsorption and its oxidization were monitored by infrared absorption spectroscopy (IRAS) with a multiple-internal-reflection (MIR) geometry. A p-type Si(100) substrate with a resistivity of 8-12 Ωcm was used as a sample. Prior to the experiment, the sample was cleaned with buffered HF acid and sulfuric acid-hydrogen peroxide mixture solutions. The Sn precursor of TMT was introduced with a variable leak valve. A plasma excited humidified argon source was installed to the ALD chamber as shown in Fig. 1. The source gas for OH-radical is a mixture of H2O vapor and Ar made by a water bubbler. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56MHz and a RF power of 30 W. Before the ALD process, the substrate surface was treated with the plasma excited humidified argon for 5 min to be terminated with Si-OH. For the SnO2 deposition, we repeated the cycle of TMT saturation and plasma excited humidified argon at RT. The condition of TMT saturation and oxidization were determined by the MIR-IRAS experiment. In this experiment, the TMT saturation exposure and oxidization time were 2×105 Langmuir and 10 min, respectively. The oxidation state of the SnO2 film was evaluated by X-ray photoelectron spectroscopy (XPS). The thickness of the grown film was measured by spectroscopic ellipsometry. In Fig. 2, we show Sn 3d XPS spectra obtained from the RT grown SnO2 film, where we confirm the evolution of full oxidized state peak according to the increase in the ALD cycle number. We calculated the growth per cycle as 0.02 nm/cycle. In the conference, we present the results of RT ALD of SnO2 and discuss the surface-reaction mechanism based on the IRAS observation. Acknowledgement; This work was partly supported by JST-CREST, JSPS KAKENHI Grant Numbers 15H03536 and 15K13299. Figure 1

Organic photovoltaics (OPVs) are considered to have a great potential to solve future energy supply scenarios due to their advantages such as low production and material costs. The power conversion efficacy and lifetime of bulk heterojunction OPVs have been significantly increasing in the last decade, although further improvements will be required for the large-scale commercialization. Because the OPV cell includes a stack of several thin layers, a certain percentages of light energy is always lost by the reflection at the interfaces between the different materials and the absorption in the layers different from the photoactive layer. In addition, due to a low carrier mobility of organic semiconductors, the active layer of OPVs should be very thin (around 100 nm), which makes it difficult to fully absorb incident light. To enhance light absorption in the thin active layer, it is important to adequately design antireflection (AR) system that can trap light into OPVs. Recently, many studies on the AR technique have applied the moth eye texture, which is a nanostructure inspired by the corneal surface of moth’s eyes. In the moth eye coating, the device surface is covered with two-dimensional array of cones with a period and height of a few hundred nanometers. Since the effective refractive index (RI) within the moth eye gradually changes in the direction of the cone axis, the level of reflection can be significantly weakened. In cases where the moth eye texturing is applied to OPVs, it is required that the material used in the texture should have compatibility with the advantage of the OPVs, such as low costs. Therefore, in this study, we employ moth eye structure made by organic polymers, since the textured pattern can be fabricated cost-effectively by nanoimprint lithography with polymeric resists. To reduce the effects of optical mismatch between the low-RI organic polymers and high-RI materials in the OPV cell (e.g., indium-doped tin oxide), we propose a new design of AR system. In this system, the hybrid AR structure, which is composed of the moth eye and multilayer interference coatings, is integrated with a high-RI glass substrate. We numerically investigate the optical properties of OPVs and demonstrate that the proposed AR system is quite useful for attaining broadband and omnidirectional antireflection. In addition, we experimentally measure the effect of the integrated AR design on the photocurrent generation of OPVs to verify the simulation results. Acknowledgement: This study was partially supported by KAKENHI (26390025) from the Japanese government, and by JST, CREST.

Dye sensitized solar cells (DSCs) have attracted much attention since the DSCs have cost advantages compared with the conventional Si solar cells. To achieve the high power conversion efficiency in the DSC, it is necessary to enhance the dye adsorption on the TiO2 nanoparticles. To achieve the high-density adsorption, we examined the TiO2 coating on the TiO2 nanoparticles since it might play a role for over-coating on naturally contaminated impurities on the nanoparticle surface. In addition, to obtain high power conversion efficiency in the DSCs, it is necessary to prevent carrier recombination between the electrolyte and TiO2 nanoparticle electrode. It is assumed that the recombination can be prevented by an energetic barrier of SiO2 between TiO2 / electrolyte. To deposit TiO2 on the nanoparticle, we used a plasma enhanced atomic layer deposition (ALD). The precursor was tetrakis(dimethylamino) titanium (TDMAT). The oxidizing agent was plasma-excited humidified argon. The growth per cycle of TiO2 is estimated as 0.15 nm/cycle. To deposit SiO2 on the TiO2 coated nanoparticles, we used the same ALD system. The precursor was tris(dimethylamino)silane (TDMAS). The oxidizing agent was the same oxidizer as that in case of TiO2. The growth per cycle of SiO2 is estimated as 0.066 nm/cycle. In this experiment, we used N719 as the sensitizing dye. We show J-V characteristics of the DSCs with the SiO2 and TiO2 combination coating in figure 1. The short circuit current density is improved from 10.04 mA/cm2 to 13.16 mA/cm2 while the open circuit voltage remains unchanged around 0.74 V. With the 10 cycle ALD of TiO2 and one cycle ALD of SiO2, the power conversion efficiency is improved from 5.41 % to 7.03 %. We consider that the combination coating prevents the carrier recombination between the electrolyte and ALD-TiO2 coated nanoparticle electrode. Acknowledgement; This work was partly supported by JST-CREST, JSPS KAKENHI Grant Numbers 15H03536 and 15K13299. Figure 1

Size of semiconductor devices in large-scale integration has reached the submicron range where gate oxide films in metal oxide semiconductor (MOS) devices need to be fabricated at a nanometer scale. Atomic layer deposition (ALD) is a technology for depositing dielectric films with monolayer precision by repeating adsorption of a source gas on substrate that is subsequently reactivated for further adsorption [1]. Zirconium oxide (ZrO2) is believed to be a candidate as the high-k gate oxide material [2]. The growth temperature for the ZrO2 deposition has been desired to be decreased to near room temperature (RT) because the interfacial layer is formed by the solid phase reaction with heating process [3]. In this work, we developed a RT atomic layer deposition of ZrO2 with tetrakis (ethylmethylamino) zirconium (TEMAZ) and a remote-plasma excited water vapor. A p-type Si(100) substrate with a resistivity of 8-12 Ωcm was used as a sample. Prior to the experiment, the sample was cleaned with a buffered HF acid solution and sulfuric acid-hydrogen peroxide mixture. TEMAZ as the zirconium precursor was introduced with a variable leak valve. An induction plasma system generating oxidizing gas was installed to the ALD chamber as shown in Fig.1. The source gas for the oxidizing gas is a mixture of H2O vapor and Ar gas. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56MHz and a RF power of 30 W. Before the ALD process, the substrate surface was treated with the plasma excited water vapor for 5 min to be terminated with OH groups. For the ZrO2 deposition, we repeated the cycle of TEMAZ saturation and the oxidizing gas treatment at RT. The TEMAZ exposure was set to 1.12×10-3 Torr×100 s. The saturation of TEMAZ on the hydroxylated surface has been confirmed by the IR absorption spectroscopy. The plasma excited oxidizing gas was injected for 150 s. The oxidization state of the ZrO2 film was evaluated by X-ray photoelectron spectroscopy (XPS). The thickness of the grown film was measured by spectroscopic ellipsometry. Fig.2 shows Zr3d spectra obtained from ZrO2 on Si grown by the present ALD. According to the increase in the ALD cycles, the Zr3d5/2 peak at around 181.9 eV evolves. The peak position indicates the full oxidized ZrO2 growth on Si [4]. Fig.3 shows the ZrO2 thickness as a function of the ALD cycle. The linear increase of ZrO2 thickness with the ALD cycle indicates that the ZrO2 is grown in the ALD mode. The growth rate is estimated to be 0.14 nm/cycle. This value is comparable with those released in the conventional thermal ALD studies [5]. To conclude, we developed the non-heating, RT ALD of ZrO2 with the plasma enhanced technology. We are now investigating the electrical characteristics of ZrO2 MOS on Si and Ge, which will be released elsewhere. The RT grown ZrO2 films might be also applicable for the anticorrosion coatings on plastic material. In the conference, we present not only the details of growth experiment but also discuss the growth kinetics of RT ALD. Acknowledgement This work was partly supported by JST-CREST. We would like to express the deepest appreciation to AIR-LIQUIDE for the high quality precursor of TEMAZ. References [1] S. M. George, Chemical Reviews, 110 (2010) 111. [2] D. Q. Xiao, G. He, P. Jin, J. Gao, J. W. Zhang, X. F. Chen, C. Y. Zheng, M. Zhang, Z. Q. Sun, Journal of Alloys and Compounds, 649 (2015) 1273. [3] C. M. Perkins, B. B. Triplett, P. C. Mclntyre, K. C. Saraswat, S. Haukka, and M. Tuominen, Applied Physics Letters, 78 (2001) 2357. [4] D. Majumdar, D. Chatterjee, Journal of Applied Physics, 70 (1991) 988. [5] K. Kukli, M. Ritala, and M. Leskelä, Chemical Vapor Deposition, 6 (2000) 297. Figure 1

Organic photovoltaics (OPVs) have been receiving growing interest, because they can provide large area and low cost solar cells for next generation. A power conversion efficiency (PCE) of more than 10 % under AM 1.5 illumination has been reported for the OPVs, although higher level of PCE is required for large-scale commercialization. Since the maximum thickness of light absorbing layer (around 100 nm) is determined by the low carrier mobility of organic semiconductors, it is important to develop antireflection technologies that can enhance light trapping in the thin absorbing layer. A popular method for analyzing light propagation within solar cells is the finite-difference time-domain (FDTD) simulation. In the FDTD method, the electric and magnetic field are spatially discretized on the grid and the temporal evolution of the field intensities is obtained through numerical integration. An advantage of the FDTD method is that it can obtain optical response for a wide wavelength range in a single simulation by Fourier transforming the results obtained by a brief input pulse. However, the FDTD simulation suffers from a considerable increase in calculation time when there is a glass substrate in the light path, which is much thicker than the other material layers within solar cells. To overcome this problem, in this study, we explore a new technique for FDTD simulation, to significantly reduce computational cost in the presence of a thick substrate, and apply this technique to the optical design of moth eye antireflection coatings on OPVs. In the proposed method, the absorption spectrum is averaged to eliminate the interference effect of light passing through a thick glass substrate and reproduce incoherent light addition within the substrate. We compare the proposed averaging method with the other two types of averaging methods, and show that the proposed algorithm gives the most accurate solution. In addition, our method is quite robust and independent of detailed values of control parameters. The validity of the results is checked by the comparison with the results obtained by the characteristic matrix method. In addition, we apply the proposed method to optimize the geometric pattern of moth eye array and maximize light trapping in OPVs. The results show that the combination of the FDTD simulation with our averaging method is quite useful to design broadband antireflection coatings for solar cells having thick glass substrates.

Aluminum oxide (Al2O3) is well known as an oxide coating material. Al2O3 is also used as a barrier layer preventing water moisture and oxygen for organic light emitting diodes (OLEDs) [1]. Al2O3 has been also studied as an anticorrosion coating material [2]. On the other hand, Al2O3 has been studied as a passivation layer for Si solar cells [3]. The growth temperature for the Al2O3 deposition has been desired to be decreased to room temperature (RT) because the devices mentioned above have been demonstrated to be fabricated on plastic or flexible substrates for organic electronics. In this work, we developed RT atomic layer deposition of Al2O3 with trimethylaluminum (TMA) and a remote-plasma excited water vapor. A p-type Si(100) substrate with a resistivity of 8-12 Ωcm was used as a sample. Prior to the experiment, the sample was cleaned with a buffered HF acid solution and a sulfuric acid-hydrogen peroxide mixture solution. TMA as the aluminum precursor was introduced with a mass flow controller (MFC). A remote plasma system generating oxidizing gas was installed to the ALD chamber as shown in Fig.1. The source gas for the oxidizing gas is a mixture of H2O vapor and Ar gas. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56MHz and a RF power of 30 W. Before the ALD process, the substrate surface was treated with the plasma excited water vapor for 5 min to be terminated with OH groups. For the Al2O3 deposition, we repeated the cycle of TMA saturation and the oxidizing gas treatment at RT. The TMA exposure was set to 1.67×10-3 Torr×15 s. The saturation of TMA on the hydroxylated surface has been confirmed by the IR absorption spectroscopy. The plasma excited oxidizing gas was injected for 2 min. The oxidization state of the Al2O3 film was evaluated by X-ray photoelectron spectroscopy (XPS). The thickness of the grown film was measured by spectroscopic ellipsometry. Fig.2 shows Al2p spectra obtained from Al2O3 on Si grown by the present ALD. According to the increase in the ALD cycles, the Al2p peak at around 74.4 eV evolves. The peak position of 74.4 eV indicates the Al2O3 growth on Si [4]. Fig.3 shows the Al2O3 thicknesses as a function of the ALD cycle. The linear increase of Al2O3 thickness with the ALD cycle indicates that the Al2O3 is grown in the ALD mode. The growth rate is estimated to be 0.15 nm/cycle. This value is comparable with those released in the previous RT ALD studies [4-6]. We checked the composition of Al and O on the ALD grown Al2O3 film with XPS. The ratio of Al and O was calculated to be 1:1.83. The refractive index of our Al2O3 film was measured to be 1.56 at 633 nm that is the same value as that of RT grown Al2O3 reported elsewhere [7]. To conclude, we developed the non-heating, RT ALD of Al2O3 with the remote plasma source. We are now investigating the gas barrier property. The RT grown Al2O3 films might be applicable for the barrier layer of water moisture and oxygen on flexible and soft materials. References [1] P. F. Carcia, R. S. McLean, M. H. Reilly, M. D. Groner, S. M. George, Applied Physics Letters, 89 (2006) 031915. [2] Belén Díaz, Emma Härkönen, Jolanta Swiatowska, Vincent Maurice, Antoine Seyeux, Philippe Marcus, Mikko Ritala, Corrosion Science, 53 (2011) 2168. [3] B. Vermang, H. Goverde, A. Uruena, A. Lorenz, E. Cornagliotti, A. Rothschild, J. John, J. Poortmans, R. Mertens, Solar Energy Materials & Solar Cells, 101 (2012) 204. [4] Seong Keun Kim, Suk Woo Lee, Cheol Seong Hwang, Yo-Sep Min, Jeong Yeon Won, and Jaehack Jeong, Journal of The Electrochemical Society, 153 (2006) F69. [5] M. D. Groner, F. H. Fabreguette, J. W. Elam, and S. M. George, Chemistry of Materials, 16 (2004) 639. [6] S. E. Potts, W. Keuning, E. Langereis, G. Dingemans, M. C. M van de Sanden, and W. M. M. Kessels, Journal of The Electrochemical Society, 157 (2010) P66. [7] S. E. Potts, L. Schmalz, M. Fenker, B. Díaz, J. Swiatowska, V. Maurice, A. Seyeux, P. Marcus, G. Radnóczi, L. Tóth, and W. M. M. Kessels, Journal of The Electrocemical Society, 158 (2011) C132. Figure 1

Facile and eco-friendly methods have been developed for the fabrication of ultrafine nanoparticles of iron based oxides. Initially, mesoporous α-Fe2O3 nanoparticles were prepared by the green tea mediated hydrothermal method. The nanoparticles of α-Fe2O3 were highly pure and well crystallized with an average particle size of 60 nm. For the fabrication of ultrafine nanoparticles, the as-prepared α-Fe2O3 were dispersed in propanol and sonicated for 1.5 h. TEM analysis confirmed the formation of single-crystalline nanoparticles with a mean size of 15 nm. The ultrafine nanoparticles showed improved performance when applied in a solar cell. We also prepared Gd and Ti doped BiFeO3 microparticles by solid state reaction technique, which was then subjected to ultrasonication for the fabrication of ultrafine nanoparticles. The average particles size of the sample was found to be 12 nm. The ultrafine nanoparticles and their bulk counterparts were successfully applied to a solar cell.

The sizes of integrated semiconductor devices such as metal oxide semiconductor (MOS), have reached to submicron range where the gate oxide films are needed to fabricate at a nanometer scale. Atomic layer deposition (ALD) is a potential technique for depositing dielectric films with monolayer precision by repeating adsorption of a source gas on a substrate that is subsequently reactivated for further adsorption [1]. HfO2 is believed to be a candidate as the high-k gate oxide material [2]. The growth temperature for the HfO2 deposition has been desired to be decreased to near room temperature because the interfacial layer is formed by the solid phase reaction with heating processes [3]. We developed a room-temperature (RT) atomic layer deposition technique for HfO2 deposition by using tetrakis(ethylmethylamino)-hafnium (TEMAH) as a precursor and a remote-plasma excited oxidizing gas. A p-type Si(100) substrate with a resistivity of 8-12 Ωcm was used as a sample. Prior to the experiment, the sample was cleaned with buffered HF acid solution and sulfuric acid-hydrogen peroxide mixture solution. As a hafnium source, TEMAH precursor was introduced in a variable leak valve. A remote-plasma system generating excited oxidizing gas was installed to the ALD chamber as shown in Fig.1. The source gas for the oxidizing gas is a mixture of H2O vapor and a carrier gas. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56MHz and a RF power of 30 W. Before the ALD process, the substrate surface was treated with the plasma excited oxidizing gas for 5 min to be terminated with OH groups. For the HfO2 deposition, we repeated the cycle of TEMAH saturation and the oxidizing gas treatment at RT. The TEMAH exposure was set to 1.67×10-3 Torr×60 s. The saturation of TEMAH on the hydroxylated Si surface has been confirmed by IR absorption spectroscopy. The plasma excited oxidizing gas was injected for 2 min. The oxidization state of HfO2 film was evaluated by X-ray photoelectron spectroscopy (XPS). The thickness of the grown film was measured by spectroscopic ellipsometry. Fig.2 shows XPS spectra for Hf4f of HfO2 film grown on Si by the present ALD technique. The peak position of 16eV indicates the growth of HfO2 on Si. It is found that with the increase in the ALD cycles, the intensity of Hf 4f7/2 peak increases. We also checked the composition of HfO2 using XPS analysis. The ratio of Hf and O was calculated to be 1:2.06. The small amount of N as the impurity was detected as an impurity in the film (data not shown). We are now evaluating the concentration of the residual carbon in the film. Fig.3 shows the HfO2 thicknesses as a function of the ALD cycle. The linear increase in the HfO2 thickness with the ALD cycles indicates that the HfO2 is grown on Si with a constant rate in the ALD mode. The growth rate is estimated to be 0.26 nm/cycle. This value is comparable with those reported in previous ALD studies [4]. To conclude, we successfully developed a non-heating ALD technique for HfO2 deposition at room temperature using a remote-plasma source. We are now investigating the electrical characteristics of HfO2 grown on Si and Ge as a MOS device. Moreover, the RT grown HfO2 films might be applicable in acid proof coatings on plastic materials. Detail will be presented at the conference. References [1] S.M. George, Chemical Reviews, 110(2010) 111. [2] C. Fu, K. Chang-Liao, Y. Chang, Y. Hsu, T. Tzeng, T. Wang, D. Heh, P. Gu, M. Tsai, Microelectronic Engineering, 88(2011)1309. [3] S. Kamiyama, T. Miura, and Y. Nara, Electrochemical Solid-state Letters, 9(2006)G285. [4] J. Fan, H. Liu, Q. Kuang, B. Gao, F. Ma, Y, Hao, Microelectronics Reliability, 52(2012)1043.