Depth-profiling Pore Morphology in Nanoporous Thin Films Using Positronium Lifetime Annihilation Spectroscopy

2005 ◽  
Vol 863 ◽  
Author(s):  
Richard S. Vallery ◽  
Hua-Gen Peng ◽  
William E. Frieze ◽  
David W. Gidley ◽  
Darren L. Moore ◽  
...  
Keyword(s):  
Beam Energy ◽  
Depth Profiling ◽  
Chemical Vapor ◽  
Positron Beam ◽  
Positronium Lifetime ◽  
Implantation Depth ◽  
Chemical Vapor Deposited ◽  
Positronium Annihilation ◽  
Positronium Annihilation Lifetime Spectroscopy

AbstractPositronium annihilation lifetime spectroscopy (PALS) using a positron beam is a proven technique to characterize porosity in amorphous thin film materials. The capability to control the depth of the implanted positrons is unique to beams as compared to traditional bulk PALS techniques. By increasing the positron beam energy, positrons are implanted deeper into the film. Control of the positron implantation depth in beam-PALS allows analysis of sub- micron films, investigation of depth-dependent film inhomogeneities, determination of pore interconnection lengths, and access to buried films under barrier layers. Details on PALS depth profiling and an example of applying the technique to a plasma-enhanced-chemical-vapor- deposited (PECVD) porous film are presented.

Characterizing Porosity in Nanoporous Thin Films Using Positronium Annihilation Lifetime Spectroscopy

2002 ◽  
Vol 726 ◽  
Author(s):  
J.N. Sun ◽  
D. W. Gidley ◽  
Y.F. Hu ◽  
W.E. Frieze ◽  
S. Yang
Keyword(s):  
Pore Size ◽  
Size Distribution ◽  
Depth Profiling ◽  
Positron Beam ◽  
Bound State ◽  
Hybrid Films ◽  
Porous Films ◽  
Pore Characteristics ◽  
Positronium Annihilation ◽  
Positronium Annihilation Lifetime Spectroscopy

AbstractDepth profiled positronium annihilation lifetime spectroscopy (PALS) has been used to probe the pore characteristics (size, distribution, and interconnectivity) in thin, porous films, including silica, organic and hybrid films. PALS has good sensitivity to and resolution of all pores (both interconnected and closed) in the size range from 0.3 nm to 30 nm, even in films buried under a diffusion barrier. In this technique a focussed beam of several keV positrons forms positronium (Ps, the electron-positron bound state) with a depth distribution that depends on the selected positron beam energy. Ps inherently localizes in the pores where its natural (vacuum) annihilation lifetime of 142 ns is reduced by collisions with the pore surfaces. The collisionally reduced Ps lifetime is correlated with pore size and is the key feature in transforming a Ps lifetime distribution into a pore size distribution. In hybrid films made porous by a degradable porogen PALS readily detects a percolation threshold with increasing porosity that represents the transition from closed pores to interconnected pores. PALS is a non-destructive, depth profiling technique with the only requirement that positrons can be implanted into the porous film where Ps can form.

scholarly journals The PADME Detector

2018 ◽  
Vol 170 ◽  
pp. 01007 ◽  
Author(s):  
Paola Gianotti
Keyword(s):  
Beam Energy ◽  
Positron Beam ◽  
Precise Determination ◽  
Final State ◽  
Missing Mass ◽  
Dark Photon ◽  
Key Points ◽  
Background Events

The PADME experiment, by using the positron beam of the Frascati laboratory, aims at searching for signals of a dark photon, A′ . It will evaluate the final state missing mass of the process e+ e- → A′ γ by knowing the beam energy and measuring the four-momentum of the ordinary recoil photon. The precise determination of this quantity, and the capability to reject background events, are the key points for the success of the experiment. In this paper a description of each component of the PADME detector is given.

Determination of biaxial modulus of chemical vapor-deposited diamond films

2001 ◽  
Vol 398-399 ◽  
pp. 265-269 ◽  
Author(s):  
Qi Hua Fan ◽  
J. Grácio ◽  
E. Pereira ◽  
V. Teixeira ◽  
J.C. Tavares
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Chemical Vapor Deposited

Study of a chemical-vapor-deposited diamond thin film on a molybdenum substrate by glancing incidence X-ray diffraction

2007 ◽  
Vol 22 (4) ◽  
pp. 319-323 ◽  
Author(s):  
Jianfeng Fang ◽  
Jing Huo ◽  
Jinyuan Zhang ◽  
Yi Zheng
Keyword(s):  
Thin Film ◽  
Diffraction Analysis ◽  
Transition Layer ◽  
Chemical Vapor ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Thin Film ◽  
Chemical Vapor Deposited

The structure of a chemical-vapor-deposited (CVD) diamond thin film on a Mo substrate was studied using quasi-parallel X-ray and glancing incidence techniques. Conventional X-ray diffraction analysis revealed that the sample consists of a diamond thin film, a Mo2C transition layer, and Mo substrate. The Mo2C transition layer was formed by a chemical reaction between the diamond film and the Mo substrate during the CVD process. A method for layer-thickness determination of the thin film and the transition layer was developed. This method was based on a relationship between X-ray diffraction intensities from the transition layer or its substrate and a function of grazing incidence angles. Results of glancing incidence X-ray diffraction analysis showed that thicknesses of the diamond thin film and the Mo2C transition layer were determined successfully with high precision.

scholarly journals Determination of PMMA Residues on a Chemical-Vapor-Deposited Monolayer of Graphene by Neutron Reflection and Atomic Force Microscopy

Langmuir ◽  
2018 ◽  
Vol 34 (5) ◽  
pp. 1827-1833 ◽  
Author(s):  
Ruiheng Li ◽  
Zongyi Li ◽  
Elias Pambou ◽  
Philipp Gutfreund ◽  
Thomas A. Waigh ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Vapor ◽  
Neutron Reflection ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chemical Vapor Deposited

scholarly journals Hydrogen depth-profiling in chemical-vapor-deposited diamond films by high-resolution elastic recoil detection

2001 ◽  
Vol 78 (12) ◽  
pp. 1679-1681 ◽  
Author(s):  
Kenji Kimura ◽  
Kaoru Nakajima ◽  
Sadanori Yamanaka ◽  
Masataka Hasegawa ◽  
Hideyo Okushi
Keyword(s):  
High Resolution ◽  
Diamond Films ◽  
Depth Profiling ◽  
Chemical Vapor ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Chemical Vapor Deposited

scholarly journals Depth-profiling plasma-induced densification of porous low-k thin films using positronium annihilation lifetime spectroscopy

2002 ◽  
Vol 81 (8) ◽  
pp. 1447-1449 ◽  
Author(s):  
Jia-Ning Sun ◽  
David W. Gidley ◽  
Yifan Hu ◽  
William E. Frieze ◽  
E. Todd Ryan
Keyword(s):  
Thin Films ◽  
Depth Profiling ◽  
Positronium Annihilation ◽  
Positronium Annihilation Lifetime Spectroscopy ◽  
Low K

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

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