Examining pressure-induced phase transformations in silicon by spherical indentation and Raman spectroscopy: A statistical study

2004 ◽  
Vol 19 (10) ◽  
pp. 3099-3108 ◽  
Author(s):  
Tom Juliano ◽  
Vladislav Domnich ◽  
Yury Gogotsi
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transformations ◽  
Statistical Study ◽  
Single Crystal Silicon ◽  
Maximum Load ◽  
Spherical Indentation ◽  
Shear Stresses ◽  
Crystal Silicon ◽  
Stability Range ◽  
Unloading Rate

Unloading rate and maximum load have been previously shown to affect the response of silicon to sharp indentation, but no such study exists for spherical indentation. In this work, a statistical analysis of over 1900 indentations made with a 13.5-μm radius spherical indenter on a single-crystal silicon wafer over a range of loads (25–700 mN) and loading/unloading rates (1–30 mN/s) is presented. The location of “pop-in” and “pop-out” events, most likely due to pressure-induced phase transformations, is noted, as well as pressures at which they occur. Multiple occurrences of pop-in and pop-out events are reported. Raman micro-spectroscopy shows a higher intensity of metastable silicon phases at some depth under the surface of the residual impression, where the highest shear stresses are present. A stability range for Si-II is demonstrated and compared with previous results for Berkovich indentation.

Failure of micron scale Single Crystal Silicon bars due to torsion developed by MEMS micro instruments

1998 ◽  
Vol 518 ◽  
Author(s):  
Taher Saif ◽  
N. C. MacDonald
Keyword(s):  
Single Crystal ◽  
Single Crystal Silicon ◽  
Theory Of Elasticity ◽  
Shear Stresses ◽  
Electrostatic Actuator ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Lever Arm ◽  
Spring Constants

AbstractWe present an experimental study on a single crystal silicon (SCS) bar subjected to pure torsion using MEMS micro instruments. The bar is in the form of a pillar, anchored at one end to the silicon substrate. It is attached to a lever arm at the other end. The pillar has a minimum cross sectional area at its mid height. The cross section coincides with the (100) plane of SCS. Torsion is generated by applying two equal forces on the lever arm on either side of the pillar. Two micro instruments apply the forces. Each consists of an electrostatic actuator and a component that calibrates it. The actuator generates high force (≈ 200 µN at 50 V) and is capable of developing large displacements (≈ 10 μm). Calibration involves determination of the force generated by the actuator at an applied voltage, as well as the linear and higher order spring constants of its springs. Each microinstrument is thus calibrated independently.With the application of forces by the two micro instruments, a torque is generated which twists the pillar. The angle of twist at different applied voltages are recorded using an angular scale. The corresponding torques are determined from the calibration parameters of the actuators. Torque is applied until the pillar fractures. Two such sample pillars, samples 1 and 2, are tested. There cross sectional areas are 1 and 2.25 µm2. We find that both the pillars behave linearly until failure. The stresses prior to fracture are evaluated based on anisotropic theory of elasticity. Samples 1 and 2 fail at shear stresses of 5.6 and 2.6 GPa respectively. The fracture surfaces seem to coincide with the (111) plane of SCS.

Structural study of TiO2 thin films by micro-Raman spectroscopy

Open Physics ◽  
2006 ◽  
Vol 4 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Ahti Niilisk ◽  
Mart Moppel ◽  
Martti Pärs ◽  
Ilmo Sildos ◽  
Taavi Jantson ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Single Crystal ◽  
Anatase Phase ◽  
Single Crystal Silicon ◽  
Atomic Layer ◽  
Fused Silica ◽  
Tio2 Thin Films ◽  
Crystal Silicon ◽  
Sapphire Substrates

AbstractThe Raman spectroscopy method was used for structural characterization of TiO2 thin films prepared by atomic layer deposition (ALD) and pulsed laser deposition (PLD) on fused silica and single-crystal silicon and sapphire substrates. Using ALD, anatase thin films were grown on silica and silicon substrates at temperatures 125–425 °C. At higher deposition temperatures, mixed anatase and rutile phases grew on these substrates. Post-growth annealing resulted in anatase-to-rutile phase transitions at 750 °C in the case of pure anatase films. The films that contained chlorine residues and were amorphous in their as-grown stage transformed into anatase phase at 400 °C and retained this phase even after annealing at 900 °C. On single crystal sapphire substrates, phase-pure rutile films were obtained by ALD at 425 °C and higher temperatures without additional annealing. Thin films that predominantly contained brookite phase were grown by PLD on silica substrates using rutile as a starting material.

Reactions at the Titanium-Silicon Interface Studied Using Hot-Stage Tem

1992 ◽  
Vol 260 ◽  
Author(s):  
Amol Kirtikar ◽  
Robert Sinclair
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Phase Transformations ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Titanium Thin Films ◽  
Sputter Deposited ◽  
Titanium Silicon ◽  
Silicon Interface

ABSTRACTThe interaction of titanium thin films sputter-deposited onto single crystal silicon was studied by in situ heating experiments within the TEM. Reactions at the Ti-Si interface including amorphization, crystallization, allotropie phase transformations and agglomeration have been observed in real time and recorded on videotape. Interpretation of these recordings can yield a wealth of information on the silicidation process.

Study on Mechanical Properties of Single-Crystal Silicon Carbide by Nanoindentation

2016 ◽  
Vol 1136 ◽  
pp. 549-554 ◽  
Author(s):  
Mitsuhiro Matsumoto ◽  
Hirofumi Harada ◽  
Koichi Kakimoto ◽  
Ji Wang Yan
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Single Crystal ◽  
Loading Rate ◽  
Single Crystal Silicon ◽  
Maximum Load ◽  
Indentation Load ◽  
Machining Process ◽  
Crystal Silicon ◽  
Sic Wafer

In order to clarify the mechanical properties of single-crystal silicon carbide (SiC), nanoindentation was performed on a 4H-SiC wafer. The change of hardness with the angle between the wafer orientation flat and the indenter edge, the maximum load and the loading rate were investigated. The hardness reached maximum at an indentation load of 12 mN in the range of 3-50 mN. Hardness decreased under two conditions: when the edge of the indenter tip is parallel to the [11-20] direction, and when a very low loading rate was used. Transmission electron microscopy was used to observe dislocations and cracks under the indents. It was demonstrated that the deformation process of SiC involved three steps with respect to the increase of the indentation load. These results provide information for improving ductile machining process of single crystal SiC.

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