scholarly journals Effect of input power and gas pressure on the roughening and selective etching of SiO2/Si surfaces in reactive plasmas

2010 ◽  
Vol 17 (9) ◽  
pp. 094501 ◽  
Author(s):  
X. X. Zhong ◽  
E. Tam ◽  
X. Z. Huang ◽  
P. Colpo ◽  
F. Rossi ◽  
...  
Keyword(s):  
Input Power ◽  
Selective Etching ◽  
Gas Pressure

TESTING OF NICKEL-CHROME ALLOY AS A TIP MATERIAL FOR MULTI-TIP LANGMUIR PROBES

2014 ◽  
Vol 21 (04) ◽  
pp. 1450056 ◽  
Author(s):  
MUHAMMAD YASIN NAZ ◽  
SHAZIA SHUKRULLAH ◽  
ABDUL GHAFFAR ◽  
IMRAN SHAKIR ◽  
SAMI ULLAH ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Inductively Coupled Plasma ◽  
Electron Number Density ◽  
Diagnostic System ◽  
Input Power ◽  
Repeated Measurements ◽  
Gas Pressure ◽  
Rf Discharge ◽  
Number Density ◽  
Electron Number

The electrostatic probes are considered to be the most powerful and experimentally simplest technique for plasma characterization. The objective of the work was to test the nickel-chrome alloy as probe tip material for characterization of RF discharge plasmas. In order to meet the objective, a triple Langmuir probe diagnostic system and associated driving circuit was designed and tested in inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using this probe diagnostic, the electron temperature, electron number density and ion saturation current were measured as a function of input RF power and filling gas pressure. An increasing trend was noticed in electron temperature and electron number density with input power whilst a decreasing trend was evident in these parameters for increasing nitrogen gas pressure. The overall variations in electron temperature and electron number density after repeated measurements were ranging from 5% to 12% and 3% to 13%, respectively.

scholarly journals ELECTRON MICROSCOPIC OBSERVATION OF SPECIMENS UNDER CONTROLLED GAS PRESSURE

1962 ◽  
Vol 13 (1) ◽  
pp. 147-152 ◽  
Author(s):  
Hans Gunther Heide
Keyword(s):  
Microscopic Observation ◽  
Organic Materials ◽  
Electron Microscopic Observation ◽  
Selective Etching ◽  
Gas Pressure ◽  
Electron Microscopic ◽  
Organic Layers ◽  
Gas Layer

A technique for encasing specimens in a thin gas layer during their observation in the Siemens Elmiskop I is described. All gases can be employed at pressures up to one atmosphere. Destruction of specimens can occur in the beam; all organic specimens are particularly liable to decompose. The conditions under which this can be avoided are given. A useful application of the technique allows one to prevent specimens from drying out, as they normally do in vacuum. A further application uses the controlled removal of carbon for thinning organic layers and for selective etching of organic materials.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

Two-photon excitation fluorescence microscopy in living systems

1993 ◽  
Vol 51 ◽  
pp. 154-155 ◽  
Author(s):  
David W. Piston
Keyword(s):  
Confocal Microscopy ◽  
Fluorescence Microscopy ◽  
Singlet State ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation fluorescence microscopy provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In our fluorescence experiments, the final excited state is the same singlet state that is populated during a conventional fluorescence experiment. Thus, the fluorophore exhibits the same emission properties (e.g. wavelength shifts, environmental sensitivity) used in typical biological microscopy studies. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10−5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

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