High Temperature Anatase TiO2 Stabilization in TiO2/Si Multilayer Structures

2012 ◽  
Vol 1443 ◽  
Author(s):  
Helmut Karl ◽  
Martina Schaedler ◽  
Eugen Ruff ◽  
Bernd Stritzker

ABSTRACTIn this work TiO2/Si multilayer structures have been grown by sputtering. After rapid thermal annealing in pure inert gas or inert gas with oxygen atmosphere the multilayers have been investigated by high resolution transmission electron microscopy, μ-Raman and dynamic secondary ion mass spectrometry for their structure and anatase/rutile phase composition. It has been found that the photocatalytically more active anatase TiO2 is stabilized and that interdiffusion and chemical reaction processes were strongly hindered up to 1100°C annealing temperature in oxygen containing atmosphere. These findings are of particular importance since only at this high temperature simultaneous formation of embedded Si nanocrystallites can be achieved.

1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.


1998 ◽  
Vol 4 (3) ◽  
pp. 269-277 ◽  
Author(s):  
A. Agrawal ◽  
J. Cizeron ◽  
V.L. Colvin

In this work, the high-temperature behavior of nanocrystalline TiO2 is studied using in situ transmission electron microscopy (TEM). These nanoparticles are made using wet chemical techniques that generate the anatase phase of TiO2 with average grain sizes of 6 nm. X-ray diffraction studies of nanophase TiO2 indicate the material undergoes a solid-solid phase transformation to the stable rutile phase between 600° and 900°C. This phase transition is not observed in the TEM samples, which remain anatase up to temperatures as high as 1000°C. Above 1000°C, nanoparticles become mobile on the amorphous carbon grid and by 1300°C, all anatase diffraction is lost and larger (50 nm) single crystals of a new phase are present. This new phase is identified as TiC both from high-resolution electron microscopy after heat treatment and electron diffraction collected during in situ heating experiments. Video images of the particle motion in situ show the nanoparticles diffusing and interacting with the underlying grid material as the reaction from TiO2 to TiC proceeds.


Author(s):  
В.В. Привезенцев ◽  
В.С. Куликаускас ◽  
В.А. Скуратов ◽  
О.С. Зилова ◽  
А.А. Бурмистров ◽  
...  

AbstractSingle-crystal n -Si(100) wafers are implanted with ^64Zn^+ ions with an energy of 50 keV and dose of 5 × 10^16 cm^–2. Then the samples are irradiated with ^132Xe^26+ ions with an energy of 167 MeV in the range of fluences from 1 × 10^12 to 5 × 10^14 cm^–2. The surface and cross section of the samples are visualized by scanning electron microscopy and transmission electron microscopy. The distribution of implanted Zn atoms is studied by time-of-flight secondary-ion mass spectrometry. After irradiation with Xe, surface pores and clusters consisting of a Zn–ZnO mixture are observed at the sample surface. In the amorphized subsurface Si layer, zinc and zinc-oxide phases are detected. After irradiation with Xe with a fluence of 5 × 10^14 cm^–2, no zinc or zinc-oxide clusters are detected in the samples by the methods used in the study.


2000 ◽  
Vol 650 ◽  
Author(s):  
Te-Sheng Wang ◽  
A.G. Cullis ◽  
E.J.H. Collart ◽  
A.J. Murrell ◽  
M.A. Foad

ABSTRACTBoron is the most important p-type dopant in Si and it is essential that, especially for low energy implantation, both as-implanted B distributions and those produced by annealing should be characterized in very great detail to obtain the required process control for advanced device applications. While secondary ion mass spectrometry (SIMS) is ordinarily employed for this purpose, in the present studies implant concentration profiles have been determined by direct B imaging with approximately nanometer depth and lateral resolution using energy-filtered imaging in the transmission electron microscopy. The as-implanted B impurity profile is correlated with theoretical expectations: differences with respect to the results of SIMS measurements are discussed. Changes in the B distribution and clustering that occur after annealing of the implanted layers are also described.


2000 ◽  
Vol 5 (S1) ◽  
pp. 369-375 ◽  
Author(s):  
Seikoh Yoshida ◽  
Joe Suzuki

High-quality GaN was grown using gas-source molecular-beam epitaxy (GSMBE). The mobility of undoped GaN was 350 cm2/Vsec and the carrier concentration was 6×1016 cm−3 at room temperature. A GaN metal semiconductor field-effect transistor (MESFET) and an n-p-n GaN bipolar junction transistor (BJT) were fabricated for high-temperature operation. The high-temperature reliability of the GaN MESFET was also investigated. That is, the lifetime of the FET at 673 K was examined by continuous current injection at 673 K. We confirmed that the FET performance did not change at 673 K for over 1010 h. The aging performance of the BJT at 573 K was examined during continuous current injection at 573 K for over 850 h. The BJT performance did not change at 573 K. The current gain was about 10. No degradation of the metal-semiconductor interface was observed by secondary ion-mass spectrometry (SIMS) and transmission electron microscopy (TEM). It was also confirmed by using Si-ion implantation that the contact resistivity of the GaN surface and electrode materials could be lowered to 7×10−6 ohmcm2.


1997 ◽  
Vol 493 ◽  
Author(s):  
M. Shimizu ◽  
H. Fujisawa ◽  
S. Hyodo ◽  
S. Nakashima ◽  
H. Niu ◽  
...  

ABSTRACTThe effect of bottom electrode thickness on the electrical properties of PZT capacitors with Ir and IrO2, electrodes was investigated, with particular attention to switching endurance characteristics. Ir and IrO2 electrodes were prepared by rf magnetron sputtering. PZT films were grown by MOCVD. Secondary ion mass spectrometry (SIMS) analysis showed thick Ir and IrO2 electrodes performed well as a barrier to the PZT elements. On the other hand, strong diffusion at the interface between PZT and the electrodes was observed, when the Ir and IrO2 electrodes were thin. From transmission electron microscope (TEM) observation, it was also found that there was an amorphous intermediate layer at the interface between the PZT and the thick Ir bottom electrode. The switching endurance characteristics were influenced by the thickness of the Ir bottom electrode.


2000 ◽  
Vol 622 ◽  
Author(s):  
Jacek Jasiński ◽  
Eliana Kamińska ◽  
Anna Piotrowska ◽  
Adam Barcz ◽  
Marcin Zieliński

ABSTRACTMicrostructure and thermal stability of ZrN/ZrB2 bilayer deposited on GaN have been studied using transmission electron microscopy methods (TEM) and secondary ion mass spectrometry (SIMS). It has been demonstrated that annealing of the contact structure at 1100°C in N2 atmosphere does not lead to any observable metal/semiconductor interaction. In contrast, a failure of the integrity of ZrN/ZrB2 metallization at 800°C, when the heat treatment is performed in O2 ambient has been observed.


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