Sub-surface damage layer of microchannel plate in optical processing

2020 ◽  
Author(s):  
Jiao Lian ◽  
Yuechong Feng ◽  
Sanzhao Wang ◽  
Puguang Song ◽  
Yu Shi ◽  
...  
Keyword(s):  
Surface Damage ◽  
Microchannel Plate ◽  
Optical Processing ◽  
Damage Layer

scholarly journals Low Energy, Low Angle, Large Area Ion Polishing for Improved EBSD Indexing

2009 ◽  
Vol 17 (3) ◽  
pp. 30-35
Author(s):  
S.D. Walck ◽  
J.R. Porter ◽  
H-W. Yang ◽  
S.S. Dheda
Keyword(s):  
Current Density ◽  
Surface Defects ◽  
Incident Angle ◽  
Surface Damage ◽  
Beam Current ◽  
Mechanical Polishing ◽  
Beam Current Density ◽  
Large Area ◽  
Electron Backscattered Diffraction ◽  
Damage Layer

Good sample preparation is essential for acquiring successful electron backscattered diffraction (EBSD) patterns in the SEM. Mechanical polishing to obtain the required surface quality with minimal sub-surface defects and deformation that does not interfere with the quality of the diffraction data is, more often than not, an art form. Special polishing techniques, such as low force lapping fixtures, electrochemical-mechanical polishing, and vibratory polishing, have been used to minimize the sub-surface damage, but have not eliminated it. Ion polishing has been used to reduce the damage layer further. However, the commercially available ion systems suffer several drawbacks, including: 1) small area treatment (≤ 1 cm) 2) decreasing beam current density with accelerating voltages, and 3) the inability to process non-conducting samples. Barna and Pecz have shown that at 3 keV with an incident angle of 5° relative to the surface, approximately 25 nm of ion damage occurs in Si and GaAs, but at 250 eV, there is less than 1 nm of amorphization of the surface. They also showed that a glancing angle across the surface is essential for removing topographic features. The ion guns that have been available for ion polishing and ion etching of SEM samples typically cannot operate effectively below 3 keV because of the low current density.

Comparison of diffraction methods for measurement of surface damage in superalloys

2006 ◽  
Vol 21 (7) ◽  
pp. 1775-1781 ◽  
Author(s):  
L.N. Brewer ◽  
M.A. Othon ◽  
Y. Gao ◽  
B.T. Hazel ◽  
W.H. Buttrill ◽  
...  
Keyword(s):  
Surface Damage ◽  
High Energy ◽  
Machining Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Damage Layer ◽  
Potential Source ◽  
Machining Operations ◽  
Electron Back Scattered Diffraction ◽  
Super Alloy

Surface damage from machining operations is a potential source of failure in metallic components. The ability to quantitatively characterize the depth and extent of the damage layer is critical to controlling the machining process. Electron back scattered diffraction and synchrotron high energy x-ray diffraction were applied to the measurement of machining surface damage in a Ni-based super alloy. Both techniques clearly showed a plastic deformation profile below the surface as a function of the machining conditions used. Using the average intragrain misorientation parameter, the electron back scattered diffraction was able to quantify the amount of surface damage from one surface treatment to another. In addition, the x-ray diffraction measurements were able to simultaneously measure the elastic strain as a function of depth from the surface.

Research on the Distribution of Subsurface Damage Layer on SiC Substrate After Double-Side Lapping

2015 ◽  
Vol 14 (01) ◽  
pp. 1-10 ◽  
Author(s):  
Hai Zhou ◽  
Xiaoming Xu ◽  
Xiang Gao ◽  
Yuan Zhang
Keyword(s):  
Silicon Carbide ◽  
Surface Damage ◽  
Damage Mechanism ◽  
Processing Parameters ◽  
Subsurface Damage ◽  
Shape Measurement ◽  
Theoretic Model ◽  
Damage Layer ◽  
Silicon Carbide Substrate ◽  
Measurement Laser

In this paper, the surface damage mechanism of silicon carbide lapping process was studied. A theoretic model between the depth of subsurface damage and surface scratch of silicon carbide substrate double-side lapping has been built. An experiment of two-sided lapping combining VK-X100/X200 shape measurement laser microscopy system with HF mild chemical etching experiment on SiC substrate was processed to obtain the distribution of surface scratch and subsurface damage layer with depth. The study shows that the thickness of subsurface damage layer decreases as the depth increases, which centrally distributes in the depth of 0–15.6 μm from outer fragmentation and scratch damage layer, which accounted for about 98.6%. The result can help us to optimize processing parameters of silicon carbide substrate double-side lapping to control the depth of subsurface damage layer.

Research on Subsurface Damage of Lapping Sapphire with Diamond Fixed Abrasive

2020 ◽  
Vol 866 ◽  
pp. 143-151
Author(s):  
Jian Bin Wang ◽  
Yong Qiang Tong ◽  
Ben Chi Jiang ◽  
Da Shu ◽  
Gang Wang
Keyword(s):  
Surface Quality ◽  
Surface Damage ◽  
Subsurface Damage ◽  
Indentation Fracture ◽  
Damage Layer ◽  
Damage Depth ◽  
The Difference ◽  
Fixed Abrasive ◽  
Free Abrasive

The depth of surface/subsurface damage layer is the key index of surface quality of sapphire. In this paper, that depth model of the surface/subsurface damage lay characterized by the crack length was established according to the mechanical theory of indentation fracture. The cutting relation between abrasive and workpiece and the difference of the depth of subsurface damage crack are analyzed. It is preliminarily estimated that the length of sub-surface damage crack of free abrasive sapphire is about 2.46 times that of fixed abrasive when considering only the contact hardness of abrasive grain under static load. Diamond abrasives with size of W20 were adopted to carry out experiments in free and fixed lapping methods. The results show that the surface/subsurface damage depth is 9.87μm and 3.63μm respectively. It is easier to obtain good sub-surface quality by using the fixed abrasive method than free abrasive at the same particle size.

Cut Surface Damage to Metals from Diamond Knife Ultramicrotomy

1967 ◽  
Vol 25 ◽  
pp. 360-361
Author(s):  
J. A. Hugo ◽  
V. A. Phillips
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Recent Work ◽  
Light Microscope ◽  
Cumulative Effect ◽  
Surface Damage ◽  
Damage Layer ◽  
Transmission Electron ◽  
Cut Surface ◽  
Diamond Knife

Recent work in our laboratory has shown that cut surfaces which are perfect when viewed in the light microscope may be prepared by ultramicrotomy using a diamond knife. Alloys successfully examined include Pb-Sn, Sn-Bi, Al-Mg, Cu-Al, and Cu-Co. After a normal etch, a Sn-5% Bi alloy showed no damage by replication electron microscopy over extensive areas. Although the cut surface may be flat, the question of whether or not there is an internally damaged layer remains unanswered. This is particularly pertinent to the use of ultramicrotomed slices for transmission electron microscopy, since damage left on the cut surface would be incorporated in the next slice cut, furthermore, if the damage layer were deep there could be a cumulative effect, so that damage from two or more previous cuts could be incorporated in a slice, in addition to that resulting from the shear during cutting.

Correlation between Local Strain Distribution and Microstructure of Grinding-Induced Damage Layers in 4H-SiC(0001)

2017 ◽  
Vol 897 ◽  
pp. 177-180 ◽  
Author(s):  
Susumu Tsukimoto ◽  
Tatsuhiko Ise ◽  
Genta Maruyama ◽  
Satoshi Hashimoto ◽  
Tsuguo Sakurada ◽  
...  
Keyword(s):  
Strain Distribution ◽  
Elastic Strain ◽  
Electron Backscatter Diffraction ◽  
Local Strain ◽  
Surface Damage ◽  
Wafer Surface ◽  
Gradient Distribution ◽  
Damage Layer ◽  
Defective Region ◽  
Sic Wafer

Evaluation of surface damage layers formed by mechanical grinding processes is indispensable in epi-ready SiC wafer preparation. As well as microstructure, the analysis of local strain distribution in the damage layers gives a clue on control of the wafer quality. Advanced electron backscatter diffraction (EBSD) technique is applied to evaluate the strain distribution of the damage layers. It is revealed that the elastic strain distribution can be classified into a hierarchy of three regions with respect to depth from the surface. Combining EBSD analysis with TEM observation, large compressive elastic strain and misorientation are introduced in the highly-defective region underneath the ground wafer surface. In addition, the gradient distribution of the strain is observed clearly below the highly-defective region. The knowledge of correlating between strain distribution and microstructure is promising to control the damage layer for the wafer preparation.

Infrared Characterization of RF Sputter Etching of Polyimide Thin Films

1990 ◽  
Vol 203 ◽  
Author(s):  
S.E. Molis ◽  
D.G. Kim ◽  
S.P. Kowalczyk ◽  
J. Kim
Keyword(s):  
Thin Films ◽  
Infrared Spectroscopy ◽  
Structural Changes ◽  
Surface Damage ◽  
Ion Sputtering ◽  
Absorption Bands ◽  
Damage Layer ◽  
Intensity Changes ◽  
Argon Ion

ABSTRACTWe present infrared spectroscopy as a means of characterizing polyimide structural changes occurring by RF argon ion sputtering. Samples of PMDA-ODA polyimide on chromium coated substrates have been sputter etched from initial thicknesses of 400 Å down to 10 Å. Relative intensity changes in imide vibrational absorption bands have been interpreted in terms of orientational reordering which occurs during the ion sputtering process. The appearance of a new vibration at 1580 cm–1 in the spectra of samples etched below 50 Å is assigned as the Elu mode of graphite corresponding to a surface damage layer which is of a graphitic form.

Focused Ion Beam (FIB) Milling Damage Formed During Tem Sample Preparation of Silicon

1998 ◽  
Vol 4 (S2) ◽  
pp. 656-657 ◽  
Author(s):  
David W. Susnitzky ◽  
Kevin D. Johnson
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Semiconductor Device ◽  
Process Development ◽  
Ion Beam ◽  
Surface Damage ◽  
Development Effort ◽  
Ion Milling ◽  
Preparation Methods ◽  
Damage Layer

The ongoing reduction of scale of semiconductor device structures places increasing demands on the sample preparation methods used for transmission electron microscopy (TEM). Much of the semiconductor industry's failure analysis and new process development effort requires specific transistor, metal or dielectric structures to be analyzed using TEM techniques. Focused ion beam (FIB) milling has emerged as a valuable technique for site-specific TEM sample preparation. FIB milling, typically with 25-50kV Ga+ ions, enables thin TEM samples to be prepared with submicron precision. However, Ga+ ion milling significantly modifies the surfaces of TEM samples by implantation and amorphization. Previous work using 90° milling angles has shown that Ga+ ion milling of Si produces a surface damage layer that is 280Å thick. This damage is problematical since the current generation of semiconductor devices requires TEM samples in the 500-1000Å thickness range.

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