Without extra heating, Al2O3 thin films were deposited on a hydrogen-terminated Si substrate etched in hydrofluoric acid by using a self-built electron cyclotron resonance （ECR） plasma-assisted atomic layer depositi...Without extra heating, Al2O3 thin films were deposited on a hydrogen-terminated Si substrate etched in hydrofluoric acid by using a self-built electron cyclotron resonance （ECR） plasma-assisted atomic layer deposition （ALD） device with Al（CH3）3 （trimethylaluminum; TMA） and O2 used as precursor and oxidant, respectively. During the deposition process, Ar was in- troduced as a carrier and purging gas. The chemical composition and microstructure of the as-deposited Al2O3 films were characterized by using X-ray diffraction （XRD）, an X-ray photo- electric spectroscope （XPS）, a scanning electron microscope （SEM）, an atomic force microscope （AFM） and a high-resolution transmission electron microscope （HRTEM）. It achieved a growth rate of 0.24 nm/cycle, which is much higher than that deposited by thermal ALD. It was found that the smooth surface thin film was amorphous alumina, and an interfacial layer formed with a thickness of ca. 2 nm was observed between theAl2O3 film and substrate Si by HRTEM. We conclude that ECR plasma-assisted ALD can growAl2O3 films with an excellent quality at a high growth rate at ambient temperature.展开更多
Polymer-assisted deposition technique has been used to deposit Al2O3 and N-doped Al2O3 （AION） thin films on Si（100） substrates. The chemical compositions, crystallinity, and thermal conductivity of the as-grown fi...Polymer-assisted deposition technique has been used to deposit Al2O3 and N-doped Al2O3 （AION） thin films on Si（100） substrates. The chemical compositions, crystallinity, and thermal conductivity of the as-grown films have been characterized by X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, and 3-omega method, respectively. Amorphous and polycrystalline Al2O3 and AlON thin films have been formed at 700 ℃ and 1000 ℃. The thermal conductivity results indicated that the effect of nitrogen doping on the thermal conductivity is determined by the competition of the increase of Al-N bonding and the suppression of crystallinity. A 67% enhancement in thermal conductivity has been achieved for the samples grown at 700 ℃, demonstrating that the nitrogen doping is an effective way to improve the thermal performance of polymer-assisted-deposited Al2O3 thin films at a relatively low growth temperature.展开更多
Atomic layer deposition （ALD） technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the grow...Atomic layer deposition （ALD） technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the growth mode defined as the arrangement of clusters on the surface during the growth is of significance. In this work, Al2O3 thin film was deposited on various interfacial species of pre-treated polyethylene terephthalate （PET, 12 μm） by plasma assisted atomic layer deposition （PA-ALD）, where trimethyl aluminium was used as the Al precursor and O2 as the oxygen source. The interracial species, -NH3, -OH, and -COOH as well as SiCHO （derived from monomer of HMDSO plasma）, were grafted previously by plasma and chemical treatments. The growth mode of PA-ALD Al2O3 was then investigated in detail by combining results from in-situ diagnosis of spectroscopic ellipsometry （SE） and ex-situ characterization of as-deposited layers from the morphologies scanned by atomic force microscopy （AFM）. In addition, the oxygen transmission rates （OTR） of the original and treated plastic films were measured. The possible reasons for the dependence of the OTR values on the surface species were explored.展开更多
Low voltage operating organic devices and circuits have been realized using atomic layer deposition deposited aluminum oxide thin film as dielectric layer. The dielectric film has per unit area capacitance of 165 nF/c...Low voltage operating organic devices and circuits have been realized using atomic layer deposition deposited aluminum oxide thin film as dielectric layer. The dielectric film has per unit area capacitance of 165 nF/cm2 and leakage current of 1 nA/cm2 at 1 MV/cm. The devices and circuits use the small-molecule hydrocarbon pentacene as the active semiconductor material. Transistors,inverters,and ring oscillators with operating voltage lower than 5 V were obtained. The mobility of organic field-effect transistors was extracted to be 0.16 cm2/Vs in saturation range,the threshold voltage is 0.3 V,and the on/off current ratio is larger than 105. The gain of inverters is estimated to be 12 at -5 V supply voltage,and the propagation delay is 0.25 ms per stage in 5-stage ring oscillators.展开更多
基金supported by National Natural Science Foundation of China(No.11175024)the Beijing Natural Science Foundation(No.1112012)+1 种基金Science and Technology on Surface Engineering Laboratorythe Beijing Education Committee(No.BM201002),2011BAD24B01,KM201110015008,KM201010015005 and PHR20110516
文摘Without extra heating, Al2O3 thin films were deposited on a hydrogen-terminated Si substrate etched in hydrofluoric acid by using a self-built electron cyclotron resonance （ECR） plasma-assisted atomic layer deposition （ALD） device with Al（CH3）3 （trimethylaluminum; TMA） and O2 used as precursor and oxidant, respectively. During the deposition process, Ar was in- troduced as a carrier and purging gas. The chemical composition and microstructure of the as-deposited Al2O3 films were characterized by using X-ray diffraction （XRD）, an X-ray photo- electric spectroscope （XPS）, a scanning electron microscope （SEM）, an atomic force microscope （AFM） and a high-resolution transmission electron microscope （HRTEM）. It achieved a growth rate of 0.24 nm/cycle, which is much higher than that deposited by thermal ALD. It was found that the smooth surface thin film was amorphous alumina, and an interfacial layer formed with a thickness of ca. 2 nm was observed between theAl2O3 film and substrate Si by HRTEM. We conclude that ECR plasma-assisted ALD can growAl2O3 films with an excellent quality at a high growth rate at ambient temperature.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60976061 and 11028409)
文摘Polymer-assisted deposition technique has been used to deposit Al2O3 and N-doped Al2O3 （AION） thin films on Si（100） substrates. The chemical compositions, crystallinity, and thermal conductivity of the as-grown films have been characterized by X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, and 3-omega method, respectively. Amorphous and polycrystalline Al2O3 and AlON thin films have been formed at 700 ℃ and 1000 ℃. The thermal conductivity results indicated that the effect of nitrogen doping on the thermal conductivity is determined by the competition of the increase of Al-N bonding and the suppression of crystallinity. A 67% enhancement in thermal conductivity has been achieved for the samples grown at 700 ℃, demonstrating that the nitrogen doping is an effective way to improve the thermal performance of polymer-assisted-deposited Al2O3 thin films at a relatively low growth temperature.
基金supported by National Natural Science Foundation of China (No.11175024)Beijing Natural Science Foundation (No.1112012),2011BAD24B01+1 种基金Scientific Research Common Program of Beijing Municipal Commission of Education(KM201110015008,KM201010015005)Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under theJurisdiction of Beijing Municipality (PHR20110516)
文摘Atomic layer deposition （ALD） technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the growth mode defined as the arrangement of clusters on the surface during the growth is of significance. In this work, Al2O3 thin film was deposited on various interfacial species of pre-treated polyethylene terephthalate （PET, 12 μm） by plasma assisted atomic layer deposition （PA-ALD）, where trimethyl aluminium was used as the Al precursor and O2 as the oxygen source. The interracial species, -NH3, -OH, and -COOH as well as SiCHO （derived from monomer of HMDSO plasma）, were grafted previously by plasma and chemical treatments. The growth mode of PA-ALD Al2O3 was then investigated in detail by combining results from in-situ diagnosis of spectroscopic ellipsometry （SE） and ex-situ characterization of as-deposited layers from the morphologies scanned by atomic force microscopy （AFM）. In addition, the oxygen transmission rates （OTR） of the original and treated plastic films were measured. The possible reasons for the dependence of the OTR values on the surface species were explored.
基金supported by the National Basic Research Program of China ("973" Project)(Grant Nos.2009CB320302,2011CB808404)the Na-tional Natural Science Foundation of China (Grant Nos.60676001,60676008)
文摘Low voltage operating organic devices and circuits have been realized using atomic layer deposition deposited aluminum oxide thin film as dielectric layer. The dielectric film has per unit area capacitance of 165 nF/cm2 and leakage current of 1 nA/cm2 at 1 MV/cm. The devices and circuits use the small-molecule hydrocarbon pentacene as the active semiconductor material. Transistors,inverters,and ring oscillators with operating voltage lower than 5 V were obtained. The mobility of organic field-effect transistors was extracted to be 0.16 cm2/Vs in saturation range,the threshold voltage is 0.3 V,and the on/off current ratio is larger than 105. The gain of inverters is estimated to be 12 at -5 V supply voltage,and the propagation delay is 0.25 ms per stage in 5-stage ring oscillators.
