Controlling the Dimensions of Laser Chemical Vapor Deposited Metallurgy

1996 ◽  
Vol 118 (1) ◽  
pp. 7-10 ◽  
Author(s):  
L. Economikos ◽  
D. E. Kotecki ◽  
R. Surprenant

The application of pyrolytic laser chemical vapor deposition (LCVD) to repair defects on multichip modules with a high circuit density requires tight control of the dimensions of the deposited metal. It is shown that by creating micro-channels into the substrate on both sides along the laser scan path, shorting to adjacent lines is eliminated and better control of deposited metal is achieved. A finite element model shows how the presence of the micro-channels reduces the temperature in the deposited material in the direction perpendicular to the laser scan, causing the deposition process to self-limit in this direction.

MRS Advances ◽  
2018 ◽  
Vol 3 (51) ◽  
pp. 3069-3074 ◽  
Author(s):  
Dominik Stümmler ◽  
Simon Sanders ◽  
Pascal Pfeiffer ◽  
Noah Wickel ◽  
Gintautas Simkus ◽  
...  

ABSTRACTAlthough Pb-based perovskite solar cells already achieve power conversion efficiencies (PCE) beyond 20 %, the use of toxic Pb is causing considerable environmental concern. As a consequence, a variety of alternative cations have been investigated to replace Pb2+ in the perovskite structure. Methylammonium bismuth iodide (MA3Bi2I9, MBI) has shown promising results for environmentally benign and chemically stable devices. While the PCE of MBI-based solar cells are still comparably low, structural improvements have been made by using chemical vapor deposition (CVD). CVD allows for the well-controlled formation of coherent and dense MBI layers in contrast to solution-processing. In this work, CVD as a possible MBI fabrication method for efficient and size-scalable solar cells is discussed. The precursors MA iodide (MAI) and Bi iodide (BiI3) are deposited in an alternating deposition process forming the desired MBI perovskite on the heated substrate. Substrate temperatures as well as deposition times of each precursor are varied with the aim of forming coherent and dense MBI layers. Optimized films are further processed to solar cell prototypes and compared with solution-processed reference devices. The results reveal that CVD possesses great potential to enable the manufacture of MBI photovoltaic (PV) devices processed in a solvent-free environment.


1991 ◽  
Vol 236 ◽  
Author(s):  
M. Tabbal ◽  
A. Lecours ◽  
R. Izquierdo ◽  
M. Meunier ◽  
A. Yelon

AbstractLaser Chemical Vapor Deposition of tungsten on GaAs from WF6 using a focused cw scanning argon-ion laser beam has been investigated. Lines have been produced using different mixtures of WF6:H2 and WF6:SiH4 and in some cases, without any reducing gas. Depositions are found to occur within a narrow process window, and are difficult to reproduce. In order to understand this process, we have performed surface analysis on GaAs samples exposed to WF6. X-Ray Photoelectron Spectroscopy studies on the interaction between WF6 and GaAs in the absence of laser illumination show that fluorinated tungsten compounds are present on the GaAs surface. Furthermore, the existence of a chemical reaction leading to the formation of GaF3 at the surface and to a loss of the stoichiometry of the substrate surface is detected. Possible mechanisms, and the effects of these reactions on the deposition process are discussed.


1996 ◽  
Vol 426 ◽  
Author(s):  
J. Kühnle ◽  
R. B. Bergmann ◽  
J. Krinke ◽  
J. H. Werner

AbstractWe compare the suitability of vapor phase and liquid phase epitaxy in a two step deposition process for the formation of thin crystalline Si films on glass substrates. In a first deposition step, we form polycrystalline Si seeding layers on glass. In a second step, we increase the thickness either by vapor phase or liquid phase epitaxy. Liquid phase epitaxy leads to growth of faceted grains of more than 100 μm in diameter but the films are not continuous. In contrast, chemical vapor deposition results in continuous, smooth films with grain sizes up to 7 μm. This difference of morphology originates from the influence of supersaturation and growth rate anisotropy. Chemical vapor deposited films exhibit surface morphologies and electrical properties that are promising for the preparation of crystalline thin film Si solar cells.


Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer

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.


Author(s):  
D.W. Susnitzky ◽  
S.R. Summerfelt ◽  
C.B. Carter

Solid-state reactions have traditionally been studied in the form of diffusion couples. This ‘bulk’ approach has been modified, for the specific case of the reaction between NiO and Al2O3, by growing NiAl2O4 (spinel) from electron-transparent Al2O3 TEM foils which had been exposed to NiO vapor at 1415°C. This latter ‘thin-film’ approach has been used to characterize the initial stage of spinel formation and to produce clean phase boundaries since further TEM preparation is not required after the reaction is completed. The present study demonstrates that chemical-vapor deposition (CVD) can be used to deposit NiO particles, with controlled size and spatial distributions, onto Al2O3 TEM specimens. Chemical reactions do not occur during the deposition process, since CVD is a relatively low-temperature technique, and thus the NiO-Al2O3 interface can be characterized. Moreover, a series of annealing treatments can be performed on the same sample which allows both Ni0-NiAl2O4 and NiAl2O4-Al2O3 interfaces to be characterized and which therefore makes this technique amenable to kinetics studies of thin-film reactions.


Author(s):  
Marylyn Bennett-Lilley ◽  
Thomas T.H. Fu ◽  
David D. Yin ◽  
R. Allen Bowling

Chemical Vapor Deposition (CVD) tungsten metallization is used to increase VLSI device performance due to its low resistivity, and improved reliability over other metallization schemes. Because of its conformal nature as a blanket film, CVD-W has been adapted to multiple levels of metal which increases circuit density. It has been used to fabricate 16 MBIT DRAM technology in a manufacturing environment, and is the metallization for 64 MBIT DRAM technology currently under development. In this work, we investigate some sources of contamination. One possible source of contamination is impurities in the feed tungsten hexafluoride (WF6) gas. Another is particle generation from the various reactor components. Another generation source is homogeneous particle generation of particles from the WF6 gas itself. The purpose of this work is to investigate and analyze CVD-W process-generated particles, and establish a particle characterization methodology.


Author(s):  
L. M. Gignac ◽  
K. P. Rodbell

As advanced semiconductor device features shrink, grain boundaries and interfaces become increasingly more important to the properties of thin metal films. With film thicknesses decreasing to the range of 10 nm and the corresponding features also decreasing to sub-micrometer sizes, interface and grain boundary properties become dominant. In this regime the details of the surfaces and grain boundaries dictate the interactions between film layers and the subsequent electrical properties. Therefore it is necessary to accurately characterize these materials on the proper length scale in order to first understand and then to improve the device effectiveness. In this talk we will examine the importance of microstructural characterization of thin metal films used in semiconductor devices and show how microstructure can influence the electrical performance. Specifically, we will review Co and Ti silicides for silicon contact and gate conductor applications, Ti/TiN liner films used for adhesion and diffusion barriers in chemical vapor deposited (CVD) tungsten vertical wiring (vias) and Ti/AlCu/Ti-TiN films used as planar interconnect metal lines.


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