共查询到20条相似文献,搜索用时 750 毫秒
1.
2.
3.
4.
《Journal of Non》2006,352(23-25):2319-2323
In this work, we report studies on the residual stress and structure of silicon oxynitride films deposited by PECVD with nitrogen atomic percent varying from 24 to 55. The stress response to thermal annealing at different temperatures is analyzed and correlated with Rutherford backscattering spectroscopy, ellipsometry, Fourier transform infrared spectroscopy, small-angle X-ray scattering spectroscopy and X-ray near edge absorption spectroscopy at the Si–K edge measurements. The results show that the stress varies from compressive to tensile for the as-deposited samples. The annealing process increased the stress value in samples that had a tensile behavior as-deposited, while decreased its value in samples with compressive stress as-grown. It is observed that the stress shifts with annealing in a way that can be correlated with the volume density of voids, also depending on the composition and structure of the films. 相似文献
5.
6.
M. L. Polignano M. Alessandri B. Crivelli R. Zonca A. P. Caricato M. Bersani M. Sbetti L. Vanzetti 《Journal of Non》2001,280(1-3):39-47
A newly developed technique for the simultaneous measurement of the oxide–silicon interface properties and of minority carrier lifetime in the silicon volume was used for a systematic study of the nitridation process of oxide films.This technique is based on the surface recombination velocity measurements, and does not require the formation of a capacitor structure, so it is suitable for the measurement of as-grown interface properties. Oxides grown both in dry and in wet environments were prepared, and nitridation processes in N2O and in NO were compared to N2 annealing processes. The effect of nitridation temperature and duration were also studied, and processes of rapid thermal oxidation (RTO) and nitridation (RTN) were compared to conventional furnace nitridation processes. Surface recombination velocity was correlated with nitrogen concentration at the oxide–silicon interface obtained by secondary ion mass spectroscopy (SIMS) measurements. Surface recombination velocity (hence surface state density) decreases with increasing nitrogen pile-up at the oxide–silicon interface, indicating that in nitrided interfaces surface state density is limited by nitridation. NO treatments are much more effective than N2O treatments in the formation of a nitrogen–rich interface layer and, as a consequence, in interface state reduction. X-ray photoelectron spectrometry (XPS) analyses were used to extend our correlation to very thin oxides (3 nm). 相似文献
7.
P. Mythili T. Kanagasekaran G. Bhagavannarayana R. Gopalakrishnan 《Journal of Crystal Growth》2012,338(1):222-227
(0.5 mol%) Dysprosium (Dy) doped bismuth silicon oxide (BSO) single crystals were grown by the Czochralski technique under air atmosphere. Detailed analysis of Dy-doped BSO with pure BSO has been studied through optical analysis. The absorption edges of pure and Dy-doped BSO crystals are found to be 405 nm and 415 nm, respectively. The shift in the absorption edge is contributed to the defect centers created in the crystal with Dy-doping. The shifts observed in the Raman spectra on doping Dy are found to be lower, when compared with the pure BSO crystal. This effect can be correlated to the lattice distortion induced by the Dy doping. The oxide formation and intrinsic defects in the BSO crystal have been identified by photoluminescence analysis. Dielectric measurements reveal that higher permeability value in the BSO sample is due to the presence of charged defects, which can be related to the space charge polarization. There is a slight decrease in dielectric constant on doping with Dy. The piezoelectric value explains the defects formed in the crystal. On poling, d33 value of BSO and Dy-doped BSO are 32 pC/N and 40 pC/N, respectively. 相似文献
8.
In this work, Ce:YAG crystal with the size of ?4 in was successfully grown by the TGT method. The optical and scintillation properties of as-grown Ce:YAG crystals were investigated. Three obvious absorption bands at 223, 340 and 460 nm and two weak color-center absorption bands at 296 and 370 nm are observed in as-grown Ce:YAG crystal. Fluorescence with an emission peak at 398 nm is observed due to the color centers, and absorption bands of the color centers can be eliminated by annealing in O2 or H2 atmosphere at 1673 K for 24 h. Yellow-green fluorescence centered at 530 nm is found when the crystal was excited at 460 nm and the 530 nm excitation spectrum shows two peaks at 340 and 460 nm. X-ray fluorescence spectrum of as-grown crystal shows three emission peaks at 300, 360 and 530 nm. An average light output of 1360 phe/MeV and a single exponential decay with the decay time constant of 62.97 ns are found in as-grown Ce:YAG crystal. 相似文献
9.
10.
Silicon carbide nanowires have been synthesized by carbothermal reduction, from carbon monoxide and single crystal silicon. Transmission electron microscopy and cathodoluminescence studies confirm the growth of a cubic β-SiC core, coated with an amorphous oxide shell. Planar defects, as stacking faults and rotational twins, are present on (1 1 1) planes. The formation of short thick rods or long thin wires, depending on the growth temperature and time, is discussed. 相似文献
11.
Wubing Xu Jiahe Chen Xiangyang Ma Deren Yang Longfei Gong Daxi Tian 《Crystal Research and Technology》2011,46(1):10-13
A dislocation‐free silicon single crystal doped with 1020 cm‐3 germanium (Ge) has been grown using the Czochralski (CZ) growth technique. The Ge concentration in the seed‐end and tang‐end of the crystal was 8×1019cm‐3and 1.6×1020 cm‐3, respectively. The effective segregation coefficient of Ge, the distribution of flow pattern defects (FPDs) and the wafer warpage have been characterized. Both the effective segregation coefficient and the equilibrium segregation coefficient of Ge in silicon were evaluated. Then, the density of FPDs was traced from seed‐end to tang‐end of the ingot, a suppression of FPDs by Ge doping was shown. That is probably because the Ge atoms consume free vacancies and thus a higher density of smaller voids is formed. Furthermore, the mechanical strength of wafers has also been characterized by batch warpage analysis. The warpage in the seed‐end was larger than that in the tang‐end of the ingot, showing that the mechanical strength of wafers is enhanced by Ge doping. Such improvement is interpreted by an enhanced dislocation pinning effect associated with the enhanced nucleation of grown‐in oxygen precipitates in the Ge‐doped silicon wafers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
Effusion measurements of hydrogen and of implanted helium are used to characterize the presence of voids in hydrogenated amorphous silicon (a-Si:H) materials as a function of substrate temperature, hydrogen content, etc. For undoped plasma-grown a-Si:H, interconnected voids are found to prevail at hydrogen concentrations exceeding 15–20 at.%, while isolated voids which act as helium traps appear at hydrogen concentrations ≤ 15 at.%. The concentration of such isolated voids is estimated to some 1018/cm3 for device-grade undoped a-Si:H deposited at a substrate temperature near 200 °C. Higher values are found for, e.g., doped material, hot wire grown a-Si:H and hydrogen-implanted crystalline Si. The results do not support recent suggestions of predominant incorporation of hydrogen in a-Si:H in (crystalline silicon type) divacancies, since such models predict a concentration of voids (which act as helium traps) in the range of 1021/cm3 and a correlation between void and hydrogen concentrations which is not observed. 相似文献
13.
The results of a preliminary investigation of the growth and morphology of p-terphenyl crystals grown by sublimation and by solvent evaporation methods are reported. It was observed that lozenge–shaped (001) crystal plates are obtained from xylene and benzene solution while dendritic crystals by sublimation. Crystallographic orientation of the plates and microscopic observations of as-grown crystal surfaces are also described. 相似文献
14.
15.
Boža Veličkov Anna Mogilatenko Rainer Bertram Detlef Klimm Reinhard Uecker Wolfgang Neumann Roberto Fornari 《Journal of Crystal Growth》2008,310(1):214-220
Two-inch-diameter γ-LiAlO2 single crystals were grown from the melt by Czochralski method. The crystals were examined by optical methods, high-resolution X-ray diffraction and transmission electron microscopy (TEM). Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the Li/Al ratio in the residual melts. The Li-evaporation from both melt and grown crystal is the main problem in the γ-LiAlO2 growth and has to be controlled by acting on the vertical temperature gradient. Shallow gradients increase the Li-evaporation from the crystal surface resulting in boules with a milky rim. On the other hand, steep gradients may induce cracks in the boule and enhance the Li2O escape from melt with consequent variation of the composition. ICP-OES investigations reveal that melt compositions can vary in the range from 46.5 to 50 mol% Li2O to obtain transparent LiAlO2 crystals. Beyond this value, the formation of inclusions inside the crystals is probable. We have established an optimized growth assembly, which allows remaining the melt composition stoichiometric. The as-grown crystals exhibit defects like subgrains, twins and a core of voids and fine-grained inclusions. The latter could be characterized by TEM as submicron LiAl5O8 crystallites. 相似文献
16.
An abrupt change of the crystal growth rate at temperatures in the range 1150–1080°C affects the annihilation or the agglomeration of grown-in defects such as flow pattern defects (FPD), crystal originated particles (COP), laser scattering defects (LSTD) and the defects measured by an optical precipitate profiler (OPPDs). Moreover, it is demonstrated that the densities of FPDs and LSTDs correlate with each other, and also with the cooling rate in such a temperature range. These relationships were investigated by growing several silicon single crystals in 10 kinds of hot-zone (HZ) configurations designed by using a numerical simulation. The cooling rate from 1412°C, the melting point of silicon, to 1150°C does not seem to be so important for the generation or the annihilation of these defects. 相似文献
17.
Y.C. Wu W. Hamd E. Thune A. Boulle C. Rochas R. Guinebretière 《Journal of Non》2009,355(16-17):951-959
Materials made of tin oxide nanocrystals homogeneously dispersed into a silica glass matrix have been elaborated through sol–gel processing. Addition of strong acids was used to control the hydrolysis–condensation in tin and silicon alkoxides mixed alcoholic solutions. Fourier transform infrared spectroscopy (FTIR) and Small angle X-ray scattering (SAXS) measurements show that the introduction of HCl allows to synthesize gels containing up to 50% of tin oxide precursor without significant modification of the pure silica gel network. Thermal treatments of slowly dried bulk gels induce the crystallization of tin oxide nanoparticles. After firing at 1000 °C, dense materials containing tin oxide nanocrystals (with a mean diameter close to 1–2 nm) are obtained. The crystal size distribution was estimated by X-ray diffraction line profile analysis. The narrowness of this distribution makes these materials interesting for optical applications. 相似文献
18.
19.
A. Candelori A. Paccagnella G. Raggi J. Wyss D. Bisello G. Ghidini 《Journal of Non》2001,280(1-3):193-201
We investigated the charge trapping properties of 10 nm thick oxide metal-oxide-semiconductor capacitors after 158 MeV silicon ion beam exposure up to 20 Mrad(Si) dose. Devices were biased during irradiation by a positive or negative gate voltage to drift radiation induced holes to the silicon/oxide and gate/oxide interface, respectively. Experimental results show that the radiation induced effective positive charge increases linearly with dose and is larger for the positive biased devices. The positive charge recombines with electrons injected in the oxide by Fowler–Nordheim tunnelling. After positive charge recombination a net negative charge builds up, due to electron trapping in radiation induced neutral defects. The negative charge density increases linearly with dose and it is larger for positive biased devices. The negative charge centroid is close to the oxide centre. The probability that one effective negative charge is generated by one radiation induced effective positive charge is 0.153±0.005. 相似文献
20.
《Journal of Crystal Growth》2006,286(2):476-480
Color centers and impurity defects of Ce:YAG crystals grown in reduction atmosphere by temperature gradient techniques have been investigated by means of gamma irradiation and thermal treatments. Four absorption bands associated with color centers or impurity defects at 235, 255, 294 and 370 nm were observed in as-grown crystals. Changes in optical intensity of the 235 and 370 nm bands after gamma irradiation indicate that they are associated with F+-type color center. Charge state change processes of Fe3+ impurity and Ce3+ ions take place in the irradiation process. The variations of Ce3+ ions concentration clearly indicate that Ce4+ ions exist in Ce:YAG crystals and gamma irradiations could increase the concentration of Ce3+ ions. Annealing treatments and the changes in optical density suggest that a heterovalent impurity ion associated with the 294 nm band seems to be present in the crystals. 相似文献