scholarly journals Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

MRS Advances ◽  
2019 ◽  
Vol 4 (09) ◽  
pp. 515-521
Author(s):  
Yuriy Suhak ◽  
Ward L. Johnson ◽  
Andrei Sotnikov ◽  
Hagen Schmidt ◽  
Holger Fritze

ABSTRACTTransport mechanisms in structurally ordered piezoelectric Ca3TaGa3Si2O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.

1998 ◽  
Vol 527 ◽  
Author(s):  
H. Bracht ◽  
E. E. Haller ◽  
K. Eberl ◽  
M. Cardona ◽  
R. Clark-Phelps

ABSTRACTWe report self-diffusion studies of silicon between 855 and 1388°C in highly enriched epitaxial 28Si layers. Diffusion profiles of 30Si and 29Si are determined with high resolution secondary ion mass spectrometry (SIMS). The temperature dependence of the Si self-diffusion coefficients is accurately described with an activation enthalpy of 4.76 eV and a pre-exponential factor of 560 cm2s-1. The single activation enthalpy indicates that Si self-interstitials dominate self-diffusion over the whole temperature range investigated. Self- and interdiffusion in buried Al71GaAs/Al69GaAs/71GaAs isotope heterostructures with different Al composition is measured between 800 and 1160°C. Ga self-diffusion in AlGaAs and interdiffusion of Al and Ga at the AlGaAs/GaAs interface show that Ga diffusion decreases with increasing Al composition and that the interdiffusion coefficient depends linearly on Al concentration. Furthermore Al is found to diffuse more rapidly into GaAs than Ga diffuses in GaAs. The temperature dependence of Ga and Al diffusion in GaAs and of Ga diffusion in AlGaAs is described by a single activation enthalpy in the range of 3.6±0.1 eV, but by different pre-exponential factors. Differences found for Ga and Al diffusion in GaAs and for Ga diffusion in AlGaAs with different Al concentrations are discussed.


2001 ◽  
Vol 669 ◽  
Author(s):  
Yukio Nakabayashi ◽  
Hirman I. Osman ◽  
Toru Segawa ◽  
Kazunari Toyonaga ◽  
Satoru Matsumoto ◽  
...  

ABSTRACTSilicon self–diffusion coefficients were measured in intrinsic and extrinsic silicon from870 to 1070°C using isotopically pure 30Si layer. 30Si diffusion profiles are determined by secondary ion mass spectrometry. The temperature dependence of intrinsic diffusion coefficient in bulk Si isobtained. Comparing it in heavily As-doped or B-doped Si, it is found that Si self-diffusion is entirely mediated by interstitialcy mechanism at lower temperatures below 870°C.


2006 ◽  
Vol 258-260 ◽  
pp. 554-561 ◽  
Author(s):  
Masashi Uematsu ◽  
Marika Gunji ◽  
Kohei M. Itoh

The effect of the SiO2/Si interface on oxygen self-diffusion in SiO2 during thermal oxidation was investigated using oxygen isotopes. A Si18O2 layer was first grown in 18O2 and then the sample was reoxidized in 16O2 at 900 ~ 1100 °C. The O diffusion in SiO2 during the 16O2 oxidation was investigated by secondary ion mass spectrometry (SIMS) measurements. Near the SiO2/Si interface, a significant broadening of the 18O profile toward the newly grown Si16O2 was observed. This 18O diffusion became slower with oxidation time and hence with increasing distance between 18O diffusion region and the interface. This distance-dependent 18O self-diffusion was simulated taking into account the effect of SiO generated at the interface upon oxidation and diffusing into SiO2 to enhance O self-diffusion. The simulation fits the SIMS profiles and shows that the SiO diffusion is greatly retarded by the oxidation with O2 from the oxygen-containing atmosphere and that the O self-diffusion therefore becomes distance-dependent. In addition, near the SiO2 surface, 16O diffusion profiles develop with the 16O2 oxidation time from the surface into the initially grown Si18O2. The integrated surface 16O concentration increases with oxidation time and the SiO from the interface affects the O self-diffusion near the surface as well.


1980 ◽  
Vol 15 (3) ◽  
pp. 702-710 ◽  
Author(s):  
R. W. Cahn ◽  
J. E. Evetts ◽  
J. Patterson ◽  
R. E. Somekh ◽  
C. Kenway Jackson

1998 ◽  
Vol 513 ◽  
Author(s):  
A. Boutry-Forveille ◽  
A. Nazarov ◽  
D. Ballutaud

ABSTRACTThe interaction of hydrogen (deuterium used as tracer) with Si-Si02-Si buried oxide layers (BOX) prepared by thermal oxidation or by oxygen implantation (SIMOX) are investigated using Secondary Ion Mass Spectrometry (SIMS) measurements combined with effusion experiments. The sample deuteration is performed at different temperatures between 150 and 300°C using a radiofrequency plasma. In SIMOX samples, the deuterium diffusion profiles analysed by SIMS show deuterium trapping on implantation defects, and deuterium diffusion in the silicon substrate by permeation through the oxide layer for temperatures higher than 250°C. The deuterium is still detected in the buried oxide layers after isothermal annealing at 600°C during 2 hours. The deuterium trapping at the siliconsilicon dioxide interfaces is analysed.


2008 ◽  
Vol 273-276 ◽  
pp. 685-692
Author(s):  
Masashi Uematsu ◽  
Kenzo Ibano ◽  
Kohei M. Itoh

The effect of the SiO2/Si interface on Si self-diffusion in SiO2 during thermal oxidation was investigated using silicon isotopes. Samples with natSiO2/28Si heterostructures were oxidized at 1150 ~ 1250 °C and the 30Si diffusion in 28SiO2 during the thermal oxidation was investigated by secondary ion mass spectrometry (SIMS) measurements. Near the SiO2/Si interface, a significant profile broadening of the 30Si isotope from natSiO2 toward the newly grown 28SiO2 was observed. This 30Si self-diffusivity sharply decreases with oxidation time and hence with increasing distance between 30Si diffusion region and the interface. This distance-dependent 30Si self-diffusion was simulated taking into account the effect of Si species generated at the interface upon oxidation and diffusing into SiO2 to enhance Si self-diffusion. The simulation fits the SIMS profiles and these results indicate that Si species, most likely SiO, are emitted from the SiO2/Si interface upon Si thermal oxidation to release the oxidation-induced stress, as has been predicted by recent theoretical studies. Furthermore, combined with our recent results on O self-diffusion, the diffusion behavior of the emitted SiO near the SiO2/Si interface is discussed.


2009 ◽  
Vol 289-292 ◽  
pp. 339-345
Author(s):  
Antônio Claret Soares Sabioni ◽  
Antônio Márcio J.M. Daniel ◽  
Renaud Metz ◽  
Anne Marie Huntz ◽  
François Jomard

Oxygen diffusion coefficients were determined in a commercial ZnO-based varistor by means of the gas-solid exchange method using the isotope 18O as the oxygen tracer. The diffusion annealings were performed at 892, 942, 992 and 1092oC, in an Ar + 18O2 atmosphere under an oxygen partial pressure of 0.2 atm. After the diffusion annealings, the 18O diffusion profiles were established by secondary ion mass spectrometry (SIMS). The results show an increase of the oxygen diffusion in the varistor, both in bulk and in grain boundaries, when compared to the oxygen diffusion in undoped ZnO. The increase of the oxygen bulk diffusion in the varistor agrees with an interstitial mechanism for the oxygen diffusion. The results also show that the grain boundary is a fast path for the oxygen diffusion in the varistor. However, the oxygen diffusion in the grain boundaries of the varistor seems to depend on several chemical and microstructural parameters and does not allow a simple explanation.


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