Detection of Titanium Silicide Formation and Phase Transformation by Picosecond Ultrasonics

1992 ◽  
Vol 260 ◽  
Author(s):  
H. -N. Lin ◽  
R. J. Stoner ◽  
H. J. Maris ◽  
J. M. E. Harper ◽  
C. Cabral ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Titanium Silicide ◽  
Silicon Substrates ◽  
Silicide Formation ◽  
Longitudinal Sound Velocity ◽  
Ultrasonic Echo ◽  
Before And After ◽  
Non Destructive ◽  
Ti Films ◽  
Picosecond Ultrasonics

ABSTRACTPicosecond ultrasonics is employed to study the titanium silicide formation sequence for evaporated Ti films on silicon substrates annealed at temperatures between 300 and 800 °C. The measurements show significant differences in the ultrasonic echo pattern before and after the structural phases C49 and C54 are formed, thus indicating that picosecond ultrasonics is a sensitive non-destructive probe of silicide formation. The longitudinal sound velocity has been found to be (8.3 ± 0.2) × 105 cm/sec for C49 TiSi2, and about 5% lower for the C54 phase.

Response Surface for CMOS Self-Aligned Titanium Silicide Process

1994 ◽  
Vol 342 ◽  
Author(s):  
A. K. Nanda ◽  
S. Meester ◽  
C. W. Wilkins
Keyword(s):  
Response Surface ◽  
Titanium Silicide ◽  
Silicon Substrates ◽  
Silicide Formation ◽  
Rapid Thermal Anneal ◽  
Contour Plots ◽  
Operating Window ◽  
Anneal Temperature ◽  
Central Composite ◽  
Anneal Time

ABSTRACTSputtered deposited titanium films on silicon substrates were used to study the effects of first rapid thermal anneal temperature, duration of anneal time and thickness of the titanium films for TiSi2 formation. A central composite, coupled with a cross design was used to analyze response surface. Empirical models were developed and contour plots were generated to describe the outcome of the first anneal. A window of operation to control the process of titanium silicide formation was recommended. Response surface analysis of data revealed an operating window of ±10° C for RTA1 for stable TiSi2 formation. Within this window of operation, the within wafer uniformity was found to be at its minimum. Anneal time was found to have minimum effect on the variability although sheet resistance decreases monotonically with increasing anneal time. Thickness of titanium films were found to be very critical in determining final TiSi2 thickness as determined by RBS and/or XRF techniques.

The Influence Of Stress on The Growth of Titanium Silicide Thin Films on (001) Silicon Substrates

1999 ◽  
Vol 564 ◽  
Author(s):  
S. L. Cheng ◽  
S. M. Chang ◽  
H. Y. Huang ◽  
Y. C. Peng ◽  
L. J. Chen ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Silicon Substrate ◽  
Function Analysis ◽  
Titanium Silicide ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Auto Correlation ◽  
Nucleation Sites ◽  
Auto Correlation Function ◽  
Ti Films

AbstractThe influence of stress on the enhanced formation of C54-TiSi2 phase has been investigated. Tensile stress induced by backside CoSi2 film on the silicon substrate has been found to enhance the growth of C54-TiSi2 on (001)Si. The thickness of amorphous interlayers (a-interlayers) between Ti films and silicon substrates was found to be thicker and thinner in the tensilly and compressively stressed samples, respectively. From auto-correlation function analysis, the thicker a-interlayer was found to consist of a higher density of crystallites. The crystallites provide nucleation sites for C49-TiSi2 and facilitate the formation of C49-TiSi2 of small size. The larger total area of C49-TiSi2 grain boundaries supplies more nucleation sites for the phase transformation of C49- to C54-TiSi2. Therefore, the tensile stress present in the silicon substrate promotes the formation of a-interlayer and decreases the grain size of C49- TiSi2, which increases the nucleation density of the C54-TiSi2 phase. As a result, the transformation of C49- to C54-TiSi2 phase is enhanced.

The Prs2O3 /Si(001) Interface: a Mixed Si-Pr Oxide

2003 ◽  
Vol 765 ◽  
Author(s):  
Dieter Schmeißer ◽  
Jarek Dabrowski ◽  
Hans-Joachim Müssig
Keyword(s):  
Depth Profiling ◽  
Dielectric Materials ◽  
Interface Properties ◽  
Silicide Formation ◽  
Silicate System ◽  
No Formation ◽  
Interface Characteristics ◽  
Reactive Interface ◽  
Non Destructive ◽  
Natural Way

AbstractWe studied the Pr2O3/Si(001) interface by a non-destructive depth profiling using synchrotron radiation and photo-electron spectroscopy (SR-PES) at the undulator beam line U49/2-PGM2 and ab initio calculations. Our results provide evidence that a chemical reactive interface exists consisting of a mixed Si-Pr oxide such as (Pr2O3)(SiO)x(SiO2)y. There is no formation of neither an interfacial SiO2 nor interfacial silicide: all Si-Pr bonds are oxidized and all SiO4 units dissolve in the Pr oxide. Under ultrahigh vacuum conditions, silicide formation is observed only when the film is heated above 800°C in vacuum. Interfacial silicates like (Pr2O3)(SiO)x(SiO2)y are promising high-k dielectric materials, e.g., because they represent incremental modification of SiO2 films by Pr ions, so that the interface characteristics can be similar to Si-SiO2 interface properties. The Pr silicate system formed in a natural way at the interface between Si(001) and Pr2O3 offers an increased flexibility towards integration of Pr2O3 into future CMOS technologies.

scholarly journals Assessment of Timber Roof Structures before and after Earthquakes

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 528
Author(s):  
Nikola Perković ◽  
Mislav Stepinac ◽  
Vlatka Rajčić ◽  
Jure Barbalić
Keyword(s):  
Test Methods ◽  
Timber Structures ◽  
Destructive Testing ◽  
Policy Makers ◽  
Load Bearing ◽  
Existing Structures ◽  
Roof Structure ◽  
Before And After ◽  
Timber Roof Structures ◽  
Non Destructive

The global objective of sustainable development has been greatly directed toward the preservation of existing structures. Therefore, condition assessment and reconstruction of existing timber structures have been gaining importance in recent times. This is particularly evident on timber roofs whose elements are exposed to degradation, either because of rheological effects or due to the direct influence of moisture and biological factors. In case of accidental events, such as an earthquake, the question of the structure’s condition is essential for the condition of the entire building. In order to prove the load-bearing capacity and serviceability of existing structures, as well as to check the need for reconstruction, it is necessary to define crucial parameters that are influencing the condition of materials, elements, and systems. Although there are many non destructive testing methods, the frequency and scope of their use, as well as the decision-making approach, have not been defined. In the paper, non-destructive and semi-destructive methods frequently used for timber structures are explained. A systematic review of criteria to be used in the assessment of load-bearing timber structures in a seismic active area was the main objective of this paper as well as the illustration of non-destructive and semi-destructive test methods through a case study involving roof construction of a hundred-year-old building in Zagreb, Croatia. Pre- and post-earthquake inspection was made. The overall condition of the roof structure after two significant earthquakes can be assessed as satisfactory given that the observed system is a large-span and massive roof structure. The presented results and identification of typical damages after the earthquake are presented in order to facilitate policy makers and for the future implementation of development strategies in the renovation of the city.

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