共查询到20条相似文献,搜索用时 15 毫秒
1.
T. Sameshima Y. Kaneko N. Andoh 《Applied Physics A: Materials Science & Processing》2001,73(4):419-423
50-nm thick amorphous silicon films formed on glass substrates were crystallized by rapid Joule heating induced by an electrical
current flowing in 100-nm-thick Cr strips formed adjacently to 200-nm-thick SiO2 intermediate layers. 3-μs-pulsed voltages were applied to the Cr strips. Melting of the Cr strips caused a high Joule heating
intensity of about 1×106 W/cm2. Raman scattering measurements revealed complete crystallization of the silicon films at a Joule heating energy of 1.9 J/cm2 via the SiO2 intermediate layer. Transmission electron microscopy measurements confirmed a crystalline grain size of 50–100 nm. 1-μm-long
crystalline grain growth was also observed just beneath the edge of the Cr strips. The electrical conductivity increased from
10-5 S/cm to 0.3 S/cm for 7×1017-cm-3-phosphorus-doped silicon films because of activation of the phosphorus atoms because of crystallization. The numerical analysis
showed a density of localized defect states at the mid gap of 8.0×1017 cm-3. Oxygen plasma treatment at 250 °C and 100 W for 5 min reduced the density of the defect states to 2.7×1017 cm-3.
Received: 3 April 2001 / Accepted: 9 April 2001 / Published online: 25 July 2001 相似文献
2.
Oxygen plasma and high pressure H2O vapor heat treatment were applied to fabrication of n-channel polycrystalline silicon thin film transistors (poly-Si TFTs).
13.56 MHz-oxygen-plasma treatment at 250 °C, 100 W for 5 min effectively reduced defect states of 25-nm-thick silicon films
crystallized by 30 ns-pulsed XeCl excimer laser irradiation. 1.3×106-Pa-H2O vapor heat treatment at 260 °C for 3 h was carried out in order to improve electrical properties of SiOx gate insulators and SiOx/Si interfaces. A carrier mobility of 470 cm2/V s and a low threshold voltage of 1.8 V were achieved for TFTs fabricated with crystallization at 285 mJ/cm2.
Received: 18 November 2002 / Accepted: 25 November 2002 / Published online: 11 April 2003
RID="*"
ID="*"Corresponding author. Fax: +81-42/388-7109, E-mail: tsamesim@cc.tuat.ac.jp 相似文献
3.
T. Kamiya A. Suemasu T. Watanabe T. Sameshima I. Shimizu 《Applied Physics A: Materials Science & Processing》2001,73(2):151-159
The carrier transport property of polycrystalline silicon (poly-Si:H:F) thin films was studied in relation to film microstructure,
impurity, in situ or post-annealing treatments to obtain better carrier transport properties. Poly-Si:H:F films were prepared
from SiF4 and H2 gas mixtures at temperatures <300 °C. Dark conductivity of the films prepared at high SiF4/H2 gas flow ratio (e.g., 60/3 sccm) exhibits a high value for intrinsic silicon and its Fermi level is located near the conduction
band edge. The carrier incorporation is suppressed well, either by in situ hydrogen plasma treatment or by post-annealing
with high-pressure hot-H2O vapor. It is confirmed that weak-bonded hydrogen atoms are removed by the hot-H2O vapor annealing. In addition, evident correlation between impurity concentrations and dark conductivity is not found for
these films. It is thought that the carrier incorporation in the films prepared at high SiF4/H2 gas flow ratios is related to grain-boundary defects such as weak-bonded hydrogen. By applying hot-H2O vapor annealing at 310 °C to a 1-μm-thick p-doped (400)-oriented poly-Si:H:F film, Hall mobility was improved from 10 cm2/Vs to 17 cm2/Vs.
Received: 7 August 2000 / Accepted: 2 March 2001 / Published online: 20 June 2001 相似文献
4.
Effect of oxygen vacancy on transport property of perovskite microstructures is studied theoretically. Compared with calculated and measured I-V curves, it is revealed that electron conduction plays an important role in the oxygen nonstoichiometry perovskite heterostructures even with hole-doped or un-doped material due to the oxygen vacancies. In addition, a detailed understanding of the influence of oxygen vacancy concentration and temperature on the conduction characteristics of oxide heterojunction with both forward and reverse biases is obtained by calculation. 相似文献
5.
T. Sameshima K. Sakamoto K. Asada 《Applied Physics A: Materials Science & Processing》1999,69(2):221-224
Heat treatment with high-pressure H2O vapor was applied to improve interface properties of SiO2/Si and passivate the silicon surface. Heat treatment at 180–420 °C with high-pressure H2O vapor changed SiOx films, 150 nm thick formed at room temperature by thermal evaporation in vacuum, into SiO2 films with a Si-O-Si bonding network similar to that of thermally grown SiO2 films. Heat treatment at 130 °C with 2.8×105 Pa H2O for 3 h reduced the recombination velocity for the electron minority carriers from 405 cm/s (as-fabricated 150-nm-thick
SiOx/Si) to 5 cm/s. Field-effect passivation was demonstrated by an additional deposition of defective SiOx films on the SiO2 films formed by heat treatment at 340 °C with high-pressure H2O vapor. The SiOx deposition reduced the recombination velocity from 100 cm/s to 48 cm/s.
Received: 1 March 1999 / Accepted: 28 March 1999 / Published online: 24 June 1999 相似文献
6.
Kunio Yubuta Teruhisa Hongo Kazutaka G. Nakamura Masae Kikuchi 《Solid State Communications》2007,143(3):127-130
Microstructure of MnF2 subjected to by shock compression at 4.4 GPa was examined using transmission electron microscopy (TEM). Lamellar structure consisting of twin-related domains of rutile-structure and intergrowth of α- PbO2-type phase is observed in the electron diffraction pattern and TEM images. The crystallographic relationship between rutile and α- PbO2-type phases can be expressed as and . 相似文献
7.
Q. Huang J.-M. Liu J. Li H.C. Fang H.P. Li C.K. Ong 《Applied Physics A: Materials Science & Processing》1999,68(5):533-538
The complete (001)-oriented thin films of La0.5Sr0.5CoO3-x (LSCO) are deposited on (001) SrTiO3 substrates by pulsed laser deposition under reduced oxygen pressure. It is revealed that the c axis of the film stretches
with depleting oxygen. The magnetic, electrical, and magnetoresistive properties of the films are characterized by means of
various techniques. Significant dependence of these properties on oxygen deficiency in the films is demonstrated, with enhanced
magnetoresistance recorded for the samples deposited over a wide range of reduced oxygen pressure.
Received: 9 July 1998 / Accepted: 15 January 1999 / Published online: 31 March 1999 相似文献
8.
Honeycomb-like alignments of carbon nanotubes were prepared by pyrolysis of a metal phthalocyanine at 950 °C in an Ar/H2 flow. A simple synthetic method has been developed for a large-scale synthesis of aligned carbon nanotubes normal to a substrate
surface.
Received: 15 June 2000 / Accepted: 21 June 2000 / Published online: 2 August 2000 相似文献
9.
Dobrev D. Neumann R. Angert N. Vetter J. 《Applied Physics A: Materials Science & Processing》2003,76(5):787-790
A method for direct electrochemical metal duplication of pores in ion-track polymer membranes is described. It allows fabrication
of metallic membranes using any metal, which is readily deposited by electroplating from aqueous solutions. The metal is deposited
on one side of the template membrane, facing the anode, which is made conductive by a thin metal cladding layer. During electroplating,
the lateral tapping of the pores is prevented by applying a counter-solution from the opposite non-metallized side of the
plastic membrane, which increases dramatically the deposition overvoltage in the vicinity of the pore orifices. Such metallic
membranes can be generated with pore diameters in the nano- and micrometer range and with densities from single pores up to
106–107 pores/cm2. They can replace plastic filters in cases when an application of polymer material is not desirable. They could be advantageous
particularly in catalysis as well as in biological science and technology. Further, they may be useful as apertures and collimators
for different kinds of radiation.
Received: 14 February 2002 / Accepted: 21 May 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +49-6159/712-179, E-mail: r.neumann@gsi.de 相似文献
10.
H.Y. Wang Z.W. Ma E.Y. Jiang Y.J. He H.S. Huang 《Applied Physics A: Materials Science & Processing》1999,68(5):559-562
The structure and magnetic properties of Fe-N and Fe-Ti-N films have been studied as a function of annealing temperature Ta with a transmission electron microscope and a vibrating sample magnetometer. The as-prepared Fe-N films consist of the γ′-Fe4N and α′′-Fe16N2 phases, and the Fe-Ti-N films are composed of the γ′-Fe4N, α′′-Fe16N2, and TiN phases. The structural changes with annealing temperature in the Fe-N films are distinct. The α′′-Fe16N2 decomposes into α+γ′ phases in the Fe-N film annealed at about 300 °C, and it disappears in the film annealed at 350 °C. Annealing of the Fe-Ti-N
films shows no structural changes between room temperature (RT) and 500 °C. The saturation magnetization 4πMS and coercivity Hc of the Fe-N films change drastically with the annealing temperature Ta, whereas those of the Fe-Ti-N films do not change with Ta up to 500 °C. These results indicate that the additon of Ti may improve the thermal stability of Fe-N films.
Recieved: 6 Juli 1998 / Accepted: 19 Oktober 1998 / Published online: 10 March 1999 相似文献
11.
Flat layered structure and improved photoluminescence emission from porous silicon microcavities formed by pulsed anodic etching 总被引:2,自引:0,他引:2
Z.H. Xiong L.S. Liao X.M. Ding S.H. Xu Y. Liu L.L. Gu F.G. Tao S.T. Lee X.Y. Hou 《Applied Physics A: Materials Science & Processing》2002,74(6):807-811
Single-mode, highly directional and stable photoluminescence (PL) emission has been achieved from porous silicon microcavities
(PSMs) fabricated by pulsed electrochemical etching. The full width at half maximum (FWHM) of the narrow PL peak available
from a freshly etched PSM is about 9 nm. The emission concentrates in a cone of 10° around the normal of the sample, with
a further reduced FWHM of ∼5.6 nm under angle-resolved measurements. Only the resonant peak is present in such angle-resolved
PL spectra. No peak broadening is found upon exposure of the freshly prepared PSM to a He-Cd laser beam, and the peak becomes
somewhat narrower (∼5.4 nm) after the PSM has been stored in an ambient environment for two weeks. At optimized etching parameters,
even a 4-nm FWHM is achievable for the freshly etched PSM. In addition, scanning electron microscopy (SEM) plane-view images
reveal that the single layer porous Si formed by pulsed current etching is more uniform and flatter than that formed by direct
current (dc) etching, demonstrated by the well-distributed circular pores with small size in the former in comparison with
the irregular interlinking pores in the latter. The SEM cross-section images show the existence of oriented Si columns of
10 nm diameter along the etching direction within the active layer, good reproducibility and flat interfaces. It is thus concluded
that pulsed current etching is superior to dc etching in obtaining flat interfaces within the distributed Bragg reflectors
because of its minor lateral etching.
Received: 7 March 2001 / Accepted: 23 July 2001 / Published online: 30 October 2001 相似文献
12.
13.
C.Y. Kim H.W. Kim J.W. Chung K.S. An C.Y. Park A. Kimura A. Kakizaki 《Applied Physics A: Materials Science & Processing》1997,64(6):597-602
Received: 14 October 1996/Accepted: 17 December 1996 相似文献
14.
M. Klimenkov J. von Borany W. Matz D. Eckert M. Wolf K.-H. Müller 《Applied Physics A: Materials Science & Processing》2002,74(4):571-575
Co nanoparticles fabricated by ion beam synthesis in SiO2 films were investigated with transmission electron microscopy and superconducting quantum interference device technique.
Variation of the thermal treatment enables the formation of Co nanoclusters of different sizes ranging from 2 to 40 nm. Small
nanoclusters of about 2–3 nm are amorphous, whereas clusters above 7 nm show the configuration of cubic Co nanocrystals. Measurements
of magnetisation at temperatures between 2 K and 360 K reveal superparamagnetic behaviour for the small nanoclusters up to
3 nm and ferromagnetism for clusters above 7 nm.
Received: 12 February 2001 / Accepted: 3 May 2001 / Published online: 27 June 2001 相似文献
15.
Yusuf Atici 《Applied Physics A: Materials Science & Processing》1997,64(3):307-314
+ Si(100) and bare Si(100) wafers by low pressure chemical vapour deposition (LPCVD) at 230–280 °C. The films were investigated
by transmission electron microscopy (TEM). The cross-sectional TEM samples of W/Si(100) exhibited a fine scale interface roughness,
which was attributed to the surface preparation. Irregular W plug structures were observed depending on the predeposition
procedures. It was observed that an insufficient deposition of W films on the contact surface leads to the presence of aluminium
around and underneath the plugs. This was observed by energy dispersive X-ray spectrometry (EDX). A study, using conventional
electron diffraction, confirmed that no silicides formed at the interfaces of W-bare Si(l00) wafers.
Received: 16 December 1996/Accepted: 6 May 1997 相似文献
16.
H. L. Kwok 《Applied physics. B, Lasers and optics》2009,94(2):279-282
Organic field-effect transistors (OFETs) have received significant attention recently because of the potential application
in low-cost flexible electronics. The physics behind their operation are relatively complex and require careful consideration
particularly with respect to the effect of charge trapping at the insulator–semiconductor interface and field effect in a
region with a thickness of a few molecular layers. Recent studies have shown that the so-called “onset” voltage (V
onset) in the rubrene OFET can vary significantly depending on past illumination and bias history. It is therefore important to
define the role of the interface trap states in more concrete terms and show how they may affect device performance. In this
work, we propose an equivalent-circuit model for the OFET to include mechanism(s) linked to trapping. This includes the existence
of a light-sensitive “resistor” controlling charge flow into/out of the interface trap states. Based on the proposed equivalent-circuit
model, an analytical expression of V
onset is derived showing how it can depend on gate bias and illumination. Using data from the literature, we analyzed the I–V characteristics of a rubrene OFET after pulsed illumination and a tetracene OFET during steady-state illumination. 相似文献
17.
Z.-X. Wang J. Hu A.-G. Li M.-L. Ruan 《Applied Physics A: Materials Science & Processing》2001,73(4):463-465
When examined under a high-resolution transmission microscope (HRTEM), highly oriented pyrolitic graphite (HOPG), after ultrasound
treatment, is found to contain some bent graphitic sheets. These bent structures are ordered graphitic sheets, which have
specific bend angles that are a multiple of 30° (from 30° to 180°). We speculate that the creation and variation of bend angles
is a result of interplay between the conformation of sp3-like defects and the ultrasound wave impact.
Received 8 September 2000 / Accepted: 6 November 2000 / Published online: 23 May 2001 相似文献
18.
We report on metal (Cr, Ni, or Pd)-induced solid-phase crystallization (MISPC) of plasma-enhanced chemical-vapor-deposited
hydrogenated amorphous silicon at annealing temperatures ≤600 °C. MISPC is found to significantly reduce the thermal budget
of crystallization at annealing temperatures as low as ∼400 °C. The lowest achievable annealing temperature is found to depend
on the metal type. The metal type is also found to influence grain size and the conductivity of the polycrystalline silicon.
Received: 21 June 1999 / Accepted: 20 October 1999 / Published online: 23 February 2000 相似文献
19.
Deep level transient spectroscopy (DLTS) and high-frequency capacitance-voltage (HF-CV) measurement are used for the investigation of HfAlO/p-Si interface. The so-called “slow” interface states detected by HF-CV are obtained to be 2.68 × 1011 cm−2. Combined conventional DLTS with insufficient-filling DLTS (IF-DLTS), the true energy level position of interfacial traps is found to be 0.33 eV above the valance band maximum of silicon, and the density of such “fast” interfacial traps is 1.91 × 1012 cm−2 eV−1. The variation of energy level position of such traps with different annealing temperatures indicates the origin of these traps may be the oxide-related traps very close to the HfAlO/Si interface. The interfacial traps’ passivation and depassivation effect of postannealing in forming gas are shown by comparing samples annealed at different temperatures. 相似文献
20.
T. Omata H. Fujiwara S. Otsuka-Yao-Matsuo N. Ono 《Applied Physics A: Materials Science & Processing》2000,71(6):609-614
Indium tin oxide (ITO) and Er3+-doped ITO powders were prepared by a conventional ceramic method. The density of ITO powders and optical absorption spectra
of Er3+ ions in Er3+-doped ITO were measured as a function of the SnO2 doping level. The results obtained were discussed in terms of the trapping center for immobile electrons in ITO. Observed
densities of ITO powders were in good agreement with those calculated from their lattice parameters, assuming that the immobile
electrons were trapped at the excess interstitial oxygen. The optical absorption spectra of Er3+-doped ITO indicated that some In3+ ions in ITO were surrounded by 7 and/or 8 oxygen ions; the increase in the coordination number of In3+ from 6 in In2O3 to 7 and/or 8 in ITO must be caused by the introduction of excess interstitial oxygen into the quasi-anion site in the C-typerare-earth
lattice upon SnO2 doping. It was concluded that the immobile electrons in ITO are trapped at the excess interstitial oxygen, and that the mechanism
of conduction carrier generation and compensation upon SnO2 doping into In2O3 can be expressed by the defect equation, 2SnO2?2SnIn·+2(1-z)e′+zOi
′′+3OO
×+(1-z)/2O2.
Received: 26 November 1999 / Accepted: 20 April 2000 / Published online: 13 September 2000 相似文献