Orientations of Polycrystalline ZnO at the Buried Interface of Oxide Thin Film Transistors (TFTs): A Grazing Incidence X-ray Diffraction Study

ABSTRACTWe report on the growth and fabrication of top gate thin film transistors at low temperatures in nanocrystalline Si:H. The nanocrystalline Si:H was deposited using a VHF-PECVD plasma process at 45 MHz in a diode reactor. The material was deposited from a mixture of silane and hydrogen at a temperature of 250-300°C. Higher temperatures resulted in a loss of hydrogen from the material. The properties of the nanocrystalline Si:H were studied using x-ray diffraction and Raman spectroscopy. The material showed a high ratio (3.8) between the crystalline and amorphous peaks in the Raman spectrum. X-ray diffraction data showed the films to be predominantly oriented in <111> direction, and the grain size estimated from Scherer's formula was in the range of 12-15 nm. The doping of the material could be changed by introducing ppm levels of Boron or Phosphorus. The as-grown material was generally n type. By adding controlled amounts of B, the material could be made p type. The devices made were n-channel MISFET's with p body. The n+ source and drain layers were made from amorphous Si:H. A systematic investigation of the appropriate oxide/nitride layer to be used was undertaken. The nitride layers were grown at 250-300°C using mixtures of silane and ammonia, with a high degree of dilution by helium. The presence of helium dilution, along with post-deposition passivation by a hydrogen plasma, was found to produce reproducible, low interface defect density nitride materials. Interface state densities were measured using capacitance spectroscopy at different frequencies and temperatures and found to be in the range of 4.5x1011/cm2-eV. The breakdown strength of the nitride was measured and found to be 4 MV/cm. Proof-of-concept TFT devices were fabricated using reactive ion etching. The threshold voltage was in the range of 13-15 V, and the on/off ratio was in the range of 103.

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Energy Dispersive Grazing Incidence X-ray Diffraction Study on Organic Thin Films EpitaxiaHy Grown on Crystalline Substrate

Advances in X-ray Analysis ◽

10.1154/s0376030800023090 ◽

1995 ◽

Vol 39 ◽

pp. 659-664 ◽

Cited By ~ 1

Author(s):

Kenji Ishida ◽

Akinori Kita ◽

Kouichi Hayashi ◽

Toshihisa Horiuchi ◽

Shoichi Kal ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Film Studies ◽

Organic Thin Films ◽

Grazing Incidence ◽

X Ray Diffraction ◽

X Ray ◽

Structural Evaluation ◽

Crystalline Substrate ◽

Scattering Volume

Thin film technology is rapidly evolving today, and the characterization of the thin film and its surface have become very important issue not only from scientific but also technological viewpoints. Although x-ray diffraction measurements have been used as suitable evaluation methods in crystallography studies, its application to the structural evaluation of the thin films, especially organic one having the low electron densities, is not easy due to the small amounts of scattering volume and the high obstructive scattering noise from the substrate. However, the x-ray diffraction measurements under grazing incidence will aid not only in overcoming the such problems but also in analyzing in-plane structure of the thin films. Therefore, so-called grazing incidence x-ray diffraction (GIXD) has been recognized as one of the most powerful tools for the surface and thin film studies.

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Progress in study of mono- and multilayers and thin film structure by X-ray reflectivity, grazing incidence X-ray diffraction and spectroscopy

Russian Chemical Reviews ◽

10.1070/rc2014v083n12abeh004485 ◽

2014 ◽

Vol 83 (12) ◽

Author(s):

M A Shcherbina ◽

S N Chvalun ◽

Sergey Anatol'evich Ponomarenko ◽

Mikhail Valentinovich Kovalchuk

Keyword(s):

Thin Film ◽

Grazing Incidence ◽

Film Structure ◽

X Ray Diffraction ◽

X Ray ◽

Thin Film Structure

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Percolation of Carbon Nanoparticles in Poly(3-Hexylthiophene) Enhancing Carrier Mobility in Organic Thin Film Transistors

Advances in Materials Science and Engineering ◽

10.1155/2014/878064 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Chang-Hung Lee ◽

Chun-Hao Hsu ◽

Iu-Ren Chen ◽

Wen-Jong Wu ◽

Chih-Ting Lin

Keyword(s):

Thin Film ◽

Thin Film Transistors ◽

Carbon Nanoparticles ◽

Carrier Mobility ◽

Organic Thin Film Transistors ◽

Organic Thin Film ◽

Photoluminescence Spectra ◽

X Ray Diffraction ◽

X Ray ◽

Printing System

To improve the field-effect mobility of all-inkjet-printed organic thin film transistors (OTFTs), a composite material consisted of carbon nanoparticles (CNPs) and poly(3-hexylthiophene) (P3HT) was reported by using homemade inkjet-printing system. These all-inkjet-printed composite OTFTs represented superior characteristics compared to the all-inkjet-printed pristine P3HT OTFTs. To investigate the enhancement mechanism of the blended materials, the percolation model was established and experimentally verified to illustrate the enhancement of the electrical properties with different blending concentrations. In addition, experimental results of OTFT contact resistances showed that both contact resistance and channel resistance were halved. At the same time, X-ray diffraction measurements, Fourier transform infrared spectra, ultraviolet-visible light, and photoluminescence spectra were also accomplished to clarify the material blending effects. Therefore, this study demonstrates the potential and guideline of carbon-based nanocomposite materials in all-inkjet-printed organic electronics.

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