Interactions Of Evaporated Nickel And Silicon Thin Films

1985 ◽  
Vol 54 ◽  
Author(s):  
L. R. Zheng ◽  
L. S. Hung ◽  
J. W. Mayer

ABSTRACTInteractions of evaporated Ni and Si thin films were investigated by a combination of backseat tering spectrometry and transmission electron microscopy. The presence of amorphous Si has no significant effects on Ni2Si and NiSi formation, but it drastically lowers the formation temperature of NiSi. Experiments with evaporated thin markers established that Ni is the dominant diffusing species in the growth of the three suicides. The stability of NiSi was examined by sequential evaporation of Ni34Si66 and Ni50Si50 thin films both on Si(100) and on evaporated Si substrates. The results showed that NiSi2 grows at the expence of NiSi when the stucture is in contact with evaporated Si, while it dissociates into NiSi and Si when in contact with single crystal Si.

1990 ◽  
Vol 5 (8) ◽  
pp. 1605-1611 ◽  
Author(s):  
S. J. Golden ◽  
H. Isotalo ◽  
M. Lanham ◽  
J. Mayer ◽  
F. F. Lange ◽  
...  

Superconducting YBaCuO thin films have been fabricated on single-crystal MgO by the spray-pyrolysis of nitrate precursors. The effects on the superconductive behavior of processing parameters such as time and temperature of heat treatment and film thickness were investigated. The superconductive behavior was found to be strongly dependent on film thickness. Films of thickness 1 μm were found to have a Tc of 67 K while thinner films showed appreciably degraded properties. Transmission electron microscopy studies have shown that the heat treatments necessary for the formation of the superconductive phase (for example, 950 °C for 30 min) also cause a substantial degree of film-substrate interdiffusion. Diffusion distances for Cu in the MgO substrate and Mg in the film were found to be sufficient to explain the degradation of the superconductive behavior in films of thickness 0.5 μm and 0.2 μm. From the concentration profiles obtained by EDS analysis diffusion coefficients at 950 °C for Mg into the YBaCuO thin film and for Cu into the MgO substrate were evaluated as 3 × 10−19 m2/s and 1 × 10−17 m2/s, respectively.


2010 ◽  
Vol 638-642 ◽  
pp. 2938-2943 ◽  
Author(s):  
A.V. Mogilatenko ◽  
Frank Allenstein ◽  
M.A. Schubert ◽  
Meiken Falke ◽  
G. Beddies ◽  
...  

Thin Ni/Al and Ni/Ga layers of different atomic ratios were codeposited onto Si(001) at room temperature followed by subsequent annealing. Influence of annealing temperature on morphology and composition of ternary disilicide NiSi2-xAlx and NiSi2-xGax layers was investigated by transmission electron microscopy. Addition of Al or Ga leads to a decrease of the disilicide formation temperature from 700°C down to at least 500°C. Depending on the composition closed, uniformly oriented NiSi2-xAlx and NiSi2-xGax layers were observed after annealing at 900°C, whereas reaction of a pure Ni film with Si leads to the island formation with a mixture of A- and B-type orientations.


1993 ◽  
Vol 311 ◽  
Author(s):  
Chih M. Yang ◽  
Harry A. Atwater

ABSTRACTIn this paper we discuss the size-dependent shrinkage rate of nanometer-size Si crystals in amorphous Si thin films during ion irradiation. We obtain shrinkage rate of nanometersize crystals at low temperature under ion irradiation by studying the evolution of the crystal size distribution using transmission electron microscopy. Our results indicate that crystals less than 10 nm in diameter decrease in size faster than larger crystals under ion irradiation. In addition, we fit our data to a capillary model for growth of Si crystals in amorphous Si under ion irradiation.


2009 ◽  
Vol 42 (2) ◽  
pp. 242-252 ◽  
Author(s):  
Cyril Cayron ◽  
Martien Den Hertog ◽  
Laurence Latu-Romain ◽  
Céline Mouchet ◽  
Christopher Secouard ◽  
...  

Odd electron diffraction patterns (EDPs) have been obtained by transmission electron microscopy (TEM) on silicon nanowires grownviathe vapour–liquid–solid method and on silicon thin films deposited by electron beam evaporation. Many explanations have been given in the past, without consensus among the scientific community: size artifacts, twinning artifacts or, more widely accepted, the existence of new hexagonal Si phases. In order to resolve this issue, the microstructures of Si nanowires and Si thin films have been characterized by TEM, high-resolution transmission electron microscopy (HRTEM) and high-resolution scanning transmission electron microscopy. Despite the differences in the geometries and elaboration processes, the EDPs of the materials show great similarities. The different hypotheses reported in the literature have been investigated. It was found that the positions of the diffraction spots in the EDPs could be reproduced by simulating a hexagonal structure withc/a= 12(2/3)1/2, but the intensities in many EDPs remained unexplained. Finally, it was established that all the experimental data,i.e.EDPs and HRTEM images, agree with a classical cubic silicon structure containing two microstructural defects: (i) overlapping Σ3 microtwins which induce extra spots by double diffraction, and (ii) nanotwins which induce extra spots as a result of streaking effects. It is concluded that there is no hexagonal phase in the Si nanowires and the Si thin films presented in this work.


Author(s):  
A. Szirmae ◽  
V.U.S. Rao ◽  
R.M. Fisher

A well known catalytic effect of transition metals and particularly iron in contack with carbonaceous carbon exposed to oxidizing or hydrogenating atmospheres (02, CO-CO2, H2-H2O) has been investigated by scanning and high voltage transmission electron microscopy in a program aimed at determining the fundamental mechanisms of the gasification reactions. Samples of polycrystalline planchets and single crystal flakes of graphite were reacted at temperatures from 650°to 1100°C in “wet” and “dry” hydrogen . Quantitative electron microscope observations were supplemented by weight loss measurements and continuous gas chromatograph analysis of the CO and CH4, produced. Prior to exposure to the reacting gases, small particles of metallic iron are formed on the surface of single crystal graphite flakes or pressed carbon planchets by vacuum deposition of thin films ranging from 1 Å to 2000 Å in thickness.


1983 ◽  
Vol 25 ◽  
Author(s):  
H. Yamamoto ◽  
H. Ishiwara ◽  
S. Furukawa ◽  
M. Tamura ◽  
T. Tokuyama

ABSTRACTLateral solid phase epitaxy (L-SPE) of amorphous Si (a-Si) films vacuum-evaporated on Si substrates with SiO2 patterns has been investigated, in which the film first grows vertically in the regions directly contacted to the Si substrates and then grows laterally onto SiO2 patterns. It has been found from transmission electron microscopy and Nomarski optical microscopy that use of dense a-Si films, which are formed by evaporation on heated substrates and subsequent amorphization by Si+ ion implantation, is essentially important for L-SPE. The maximum L-SPE length of 5–6μm was obtained along the <010> direction after 10hourannealing at 600°C. The kinetics of the L-SPE growth has also been investigated.


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