Diffusional Phase Transformation under Induced Thermal Stress

1991 ◽  
Vol 230 ◽  
Author(s):  
E C Zingu ◽  
B T Mofokeng
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Elevated Temperatures ◽  
Film Structure ◽  
Intrinsic Stress ◽  
Silicide Formation ◽  
Si Substrates ◽  
Silicide Growth ◽  
Expansion Coefficients ◽  
Large Tensile Stress

AbstractWhen thin films are deposited on substrates or when compound films are formed through interdiffusion of multi-film structures, intrinsic stress develops in the various films. Thermal mismatch between the expansion coefficients of the substrate and films in multi-film structures gives rise to extrinsic stress at elevated temperaturesBy using Si<100> and rolled Al foil substrates supporting the same multi-film structure SiO2/Si/Co, the effect of extrinsic stress on interdiffusion of thin films is isolated.Silicide growth is found to be inhibited (delayed) when formed on Al substrates compared to that formed on Si substrates. The delay in silicide growth is ascribed to delamination caused by large tensile stress prior to silicide formation. The growth rate of Co2Si is found to be similar on both Al and Si substrates

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

Structural Characterization of Heteroepitaxial 3C-SiC

2012 ◽  
Vol 711 ◽  
pp. 27-30 ◽  
Author(s):  
Andrea Severino ◽  
Ruggero Anzalone ◽  
Massimo Camarda ◽  
Nicolò Piluso ◽  
Francesco La Via
Keyword(s):  
Growth Rate ◽  
Film Structure ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Transmission Electron ◽  
Crystallographic Defects ◽  
Sic Film ◽  
Sic Films

In this work, we focus our attention on the characterization of 3C-SiC films, grown within a CVD reactor, on Si substrates. It will be shown how the growth procedures influence the SiC film structure and quality with the growth rate used during the growth used as example. Evaluation of crystal structure has been conducted by X-Ray Diffraction (XRD), Raman microscopy and Transmission Electron Microscopy (TEM). Overall film quality increases if films are grown under low growth rate conditions, thanks also to an important reduction in the density of micro-twins. The trend of the full widths at half maximum (FWHMs) of SiC rocking curves, considered good ‘quality indicator’ as their broadenings are affected by crystallographic defects, as a function of 3C-SiC thickness shows a saturated regime for very thick films, due to the saturation of stacking fault density after 50 μm of growth. This work wants to suggest a reasonable path for the characterization of the material structure that can be useful, anywhere and in any time, to assess if the morphology and microstructure of our films are satisfactory and to drive towards the desired improvement.

Crystallization Process of TiNi Thin Films Sputtered at Elevated Temperatures on Pt/Si Oxide/Si and Si Oxide/Si Substrates

2000 ◽  
Vol 39 (Part 1, No. 2A) ◽  
pp. 568-571 ◽  
Author(s):  
Ick-Jun Kim ◽  
Hiroshi Nanjo ◽  
Takashi Iijima ◽  
Toshihiko Abe
Keyword(s):  
Thin Films ◽  
Crystallization Process ◽  
Elevated Temperatures ◽  
Si Substrates

Lateral Silicide Growth

1983 ◽  
Vol 25 ◽  
Author(s):  
L. R. Zheng ◽  
E. Zingu ◽  
J. W. Mayer
Keyword(s):  
Activation Energy ◽  
Low Temperatures ◽  
Lateral Diffusion ◽  
Silicide Formation ◽  
Diffusion Couples ◽  
Si Substrates ◽  
Annealing Temperatures ◽  
Metal Silicides ◽  
Silicide Growth ◽  
Si Films

ABSTRACTSilicide formation and growth kinetics have been investigated with lateral diffusion couples formed by deposition of Ni and Cr layers on patterned Si substrates and by deposition of Ni patterns on Si films. For annealing temperatures between 520 and 650°C the growth of CrSi2follows a (time)½ dependence with an activation energy of 1.4± 0.1 eV. In Ni-silicide formation at temperatures below 600°C, Ni was the predominant moving species. As the temperature increased, the motion of Si became significant. The apparent activation energy for silicide formation varied from Ea ≅ 1.4 eV for Ni motion at relatively low temperatures to Ea≅ 2.3 eV for Si motion that occurs at high temperatures. Lateral diffusion in device geometry structures resulted in degradation of contact planarity due to the penetration of metal silicides in Ni-Si structures or the erosion of silicon in Cr-Si structures.

scholarly journals Low-Field Electron Emission Capability of Thin Films on Flat Silicon Substrates: Experiments with Mo and General Model for Refractory Metals and Carbon

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3350
Author(s):  
Ivan Bizyaev ◽  
Pavel Gabdullin ◽  
Maxim Chumak ◽  
Vladislav Babyuk ◽  
Sergey Davydov ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Emission ◽  
Elevated Temperatures ◽  
Local Heating ◽  
Film Structure ◽  
Refractory Metals ◽  
Field Electron Emission ◽  
Related Factors ◽  
Low Field ◽  
Field Electron

Herein, we describe a study of the phenomenon of field-induced electron emission from thin films deposited on flat Si substrates. Films of Mo with an effective thickness of 6–10 nm showed room-temperature low-field emissivity; a 100 nA current was extracted at macroscopic field magnitudes as low as 1.4–3.7 V/μm. This result was achieved after formation treatment of the samples by combined action of elevated temperatures (100–600 °C) and the electric field. Morphology of the films was assessed by AFM, SEM, and STM/STS methods before and after the emission tests. The images showed that forming treatment and emission experiments resulted in the appearance of numerous defects at the initially continuous and smooth films; in some regions, the Mo layer was found to consist of separate nanosized islets. Film structure reconstruction (dewetting) was apparently induced by emission-related factors, such as local heating and/or ion irradiation. These results were compared with our previous data obtained in experiments with carbon islet films of similar average thickness deposited onto identical substrates. On this basis, we suggest a novel model of emission mechanism that might be common for thin films of carbon and refractory metals. The model combines elements of the well-known patch field, multiple barriers, and thermoelectric models of low-macroscopic-field electron emission from electrically nanostructured heterogeneous materials.

scholarly journals ELECTRONIC PROPERTIES OF THIN FILMS SUBLIMED FROM La@C82 AND Li@C60

NANO ◽  
2008 ◽  
Vol 03 (03) ◽  
pp. 155-160 ◽  
Author(s):  
V. N. POPOK ◽  
A. V. GROMOV ◽  
M. JÖNSSON ◽  
A. TANINAKA ◽  
H. SHINOHARA ◽  
...  
Keyword(s):  
Thin Films ◽  
Elevated Temperatures ◽  
Film Structure ◽  
Ambient Atmosphere ◽  
Room Temperature Resistivity ◽  
Electrical Measurements ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Temperature Dependences

La @ C 82 and Li @ C 60 thin films obtained by sublimation in vacuum are studied using four-probe current–voltage measurements and atomic force microscopy. In situ electrical measurements show semiconducting behavior of both films with room-temperature resistivity of 21 ± 8 and 1230 ± 50 Ω · cm for the La @ C 82 and Li @ C 60, respectively. A variable range hopping mechanism of conductance is suggested from the temperature dependences of resistance. The activation energies for electron transport are calculated for both metallofullerenes. Irreversible changes to the Li @ C 60 film structure increasing the film resistivity to values typical for C 60 are found at elevated temperatures. The effect of exposure to ambient atmosphere on the conductance of the films is discussed.

Chemical Solution Deposited BaTi03 AND SrTi03 Thin Films With Columnar Microstructure

1997 ◽  
Vol 474 ◽  
Author(s):  
S. Hoffmann ◽  
U. Hasenkox ◽  
R. Waser ◽  
C. L. Jia ◽  
K. Urban
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Formation Process ◽  
Elevated Temperatures ◽  
Film Formation ◽  
Precursor Chemistry ◽  
Si Substrates ◽  
Transmission Electron ◽  
Columnar Grain ◽  
Means Of Transmission

ABSTRACTWe show that CSD processing can be optimized in order to achieve columnar structured BaTiO3 and SrTiO3 thin films at elevated temperatures. In addition to these, columnar grain growth was also obtained for films of the solid solution (Ba0.7Sr0.3)TiO3 By controlling the film formation process, polycrystalline and columnar grained thin films were grown on Pt coated Si substrates at temperatures between 750° and 800°. The films were analyzed by glancing incidence X-ray diffraction and scanning electron microscopy. Detailed analysis on the thin films’ microstructure was performed by means of transmission electron microscopy. Based on these data, the film formation process is discussed with respect to process control and precursor chemistry. Differences in the crystallization process of BaTiO3 thin films compared to SrTiO3 films are pointed out.

Stress Relaxation During Diffusional Phase Transformation Under Induced Thermal Stress

1993 ◽  
Vol 308 ◽  
Author(s):  
E C Zingu ◽  
B T Mofokeng
Keyword(s):  
Thin Film ◽  
Growth Rate ◽  
Phase Transformation ◽  
Thermal Stress ◽  
Molar Fraction ◽  
Si Substrates ◽  
Expansion Coefficients ◽  
The Difference ◽  
Stress States ◽  
Si Thin Film

ABSTRACTThermal mismatch between the expansion coefficients of a substrate and deposited thin film gives rise to extrinsic stress in the film. Different stress states are induced into the Co/Si thin film combination by depositing the multi-layers on Al and Si substrates respectively. Interdiffusion at 360°C is found to be influenced by the extrinsic stress in the films. The difference in Co2Si growth rate on different substrates is ascribed to the difference in composition (Co molar fraction) at the Co/Co2Si and Co2Si/Si interfaces due to different stress states.

Oxygen Effect and Redistribution in Cobalt Silicide Formation

1983 ◽  
Vol 25 ◽  
Author(s):  
Chuen-Der Lien ◽  
Marc-A. Nicolet
Keyword(s):  
Growth Rate ◽  
Dose Range ◽  
Oxygen Effect ◽  
Cobalt Silicide ◽  
Silicide Formation ◽  
Si Substrate ◽  
Silicide Growth ◽  
Two Phases ◽  
Effect Of Oxygen ◽  
Kinetics Of

ABSTRACT18O was implanted in the Si substrate or in the Co overlayer to study the effect of oxygen and its redistribution during Co silicides formation. Implanted and unimplanted samples were annealed in vacuum at 450°C for different durations. Over the investigated dose range of 0.5 to 2 × 101618O/cm2 in the Co film, the phases formed upon annealing are Co2Si and CoSi, as for the unimplanted samples. The kinetics of the silicide growth is changed little by the presence of oxygen in the Co film. Oxygen accumulates at the Co2Si/Co interface. When the oxygen is implanted in the Si substrate, the higher the oxygen dose is, the slower (fasteil the growth rate of CoSi(Co2Si) becomes. Below 1 × 1016 O/cm, both phases (i.e. CoSi and Co2Si) still form; above 2 × 1016 O/cm2 , only Co2Si formsWhen two phases form, the oxygen moves deep into the Si substrate; when only Co2Si forms, the oxygen moves toward the surface.

Sign in / Sign up

Export Citation Format

Share Document