XTEM study of phase transition in MeV ion-implanted InP

Author(s):  
Fulin Xiong

MeV ion implantation into III-V compound semiconductors has attracted great attention in recent years because of its high potential for 3-dimensional device fabrication technology. However, a thorough understanding of associated physical processes involved is crucial before it can be universally applied. Our study on this subject with InP using cross sectional and high resolution transmission electron microscopy (XTEM, HRTEM) reveals clearly the structural changes occurring during MeV-ion-implantation and subsequent thermal annealing. It has lead to a better understanding of the mechanism of phase transition in InP under MeV ion irradiation.Samples of n-type InP(lOO) single crystalline wafers were implanted with 5 MeV-N-ions in room temperature with doses ranging from 1014 to 1016/cm2. Post-implantation annealing was carried out in a graphite strip heater at 500 C with ambient H2 flow.Fig. 1 shows a typical XTEM view of an implanted sample at a dose of 1 x 1016/cm2. A wide implanted layer is buried at a maximum depth of 4μm with a slightly damaged top surface. The buried layer appears as a highly disordered crystalline structure when the sample was annealed, whereas it is amorphous in an as-implanted sample.

2011 ◽  
Vol 5 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Maja Popovic ◽  
Mirjana Novakovic ◽  
Zlatko Rakocevic ◽  
Natasa Bibic

In this work, the effects of 120 keV Ar+ ion implantation on the structural properties of TiN thin films were investigated. TiN layers were deposited by d.c. reactive sputtering on Si(100) wafers at room temperature or at 150?C. The thickness of TiN layers was ~240 nm. After deposition the samples were irradiated with 120 keV argon ions to the fluencies of 1?1015 and 1?1016 ions/cm2. Structural characterization was performed with Rutherford backscattering spectroscopy (RBS), cross-sectional transmission electron microscopy (XTEM), grazing angle X-ray diffraction (XRD) and atomic force microscopy (AFM). It was found that the argon ion irradiation induced the changes in the lattice constant, mean grain size, micro-strain and surface morphology of the TiN layers. The observed micro-structural changes are due to the formation of the high density damage region in the TiN thin film structure.


Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.


Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.


1999 ◽  
Vol 5 (S2) ◽  
pp. 758-759
Author(s):  
W.L. Zhou ◽  
Y. Sasaki ◽  
Y. Ikuhara ◽  
C.J.O’Connor

Artificial defects generated by ion irradiation have been considered an efficient method to enhance the critical current density in superconducting materials. The mechanism of producing defects as flux pining centers is still an important issue since the efficiency of irradiation-induced defects in flux pinning strongly depends on their microstructures. Different types of defects have been found in heavy ion irradiation. However, there are few results that show light ion irradiation due to the target material selected, the type of light ion and energy, and the incident ion angle. Another factor is the difficulty of cross-sectional sample preparation. In this paper, a single crystal Bi2Sr2CaCu2O7-x with 11 MeV B5+ ion irradiation was observed by transmission electron microscope (TEM) from both plan and cross-sectional view.The Bi2Sr2CaCu2O7-x single crystals used for ion irradiation were prepared using the floating-zone melting method. The crystals were cleaved into thin sheets of about 20 μm thickness along the a-b plane and cut to about 2mmx2mm size.


2002 ◽  
Vol 725 ◽  
Author(s):  
T. Martens ◽  
J. D'Haen ◽  
T. Munters ◽  
L. Goris ◽  
Z. Beelen ◽  
...  

AbstractIn this paper, a clear view on the bulk microstructure of MDMO-PPV:PCBM blends as used in bulk hetero-junction organic solar cells is obtained by means of TEM (Transmission Electron Microscopy). Using TEM, 3-dimensional information is acquired on phase separated regions, formed during casting. Particle statistics illustrate quantitatively that a.o. drying conditions and choice of solvent dramatically influence the blend structure. More information about the lateral blend structure and distribution is obtained in cross-sectional view. Since blend morphology is strongly related to photovoltaic performance, TEM can be a powerful tool for understanding today's photovoltaic performances and screening new sets of materials.


1987 ◽  
Vol 97 ◽  
Author(s):  
Tadamasa Kimura ◽  
Hiroyuki Yamaguchi ◽  
Shigemi Yugo ◽  
Yoshio Adachi

ABSTRACTThe β-SiC formation process through post-implantation annealing of Si-C mixtures fabricated on Si by C-ion implantation at room temperature is studied by means of infrared absorption spectroscopy. It is shown that the formation of B-SiC from the Si-C mixtures is greatly enhanced by the subsequent irradiation of other energetic ions prior to the thermal annealing. The continuous amorphization of the Si-C mixed layers is considered to be the dominant cause for the enhancement of the B-SiC formation. The activation energy of the β-SiC formation process which is 5.3 eV without irradiation is reduced to 4.0 eV by the irradiation of 150 keV, 1 × 1017/cm2 Ar ions.


2005 ◽  
Vol 108-109 ◽  
pp. 395-400 ◽  
Author(s):  
Filippo Giannazzo ◽  
E. Bruno ◽  
S. Mirabella ◽  
G. Impellizzeri ◽  
E. Napolitani ◽  
...  

In this work, we investigate the effect of performing a high dose 20 keV He+ implant before the implantation of B at low energy (3 keV) in silicon and the subsequent thermal annealing at 800 °C. The implants were performed in laterally confined regions defined by opening windows in a SiO2 mask, in order to evidence the impact on a realistic configuration used in device fabrication. High resolution quantitative scanning capacitance microscopy (SCM) combined with cross-section transmission electron microscopy (XTEM) allowed to clarify the role of the voids distribution produced during the thermal annealing on the diffusion and electrical activation of implanted B in Si. Particular evidence was given to the effect of the uniform nanovoids distribution, which forms in the region between the surface and the buried cavity layer.


2006 ◽  
Vol 957 ◽  
Author(s):  
Rajendra Singh ◽  
R. Scholz ◽  
U. Gösele ◽  
S. H. Christiansen

ABSTRACTZnO(0001) bulk crystals were implanted with 100 keV H2+ ions with various doses in the range of 5×1016 to 3×1017 cm-2. The ZnO crystals implanted up to a dose of 2.2×1017 cm-2 did not show any surface exfoliation, even after post-implantation annealing at temperatures up to 800°C for 1 h while those crystals implanted with a dose of 2.8×1017 cm-2 or higher exhibited exfoliated surfaces already in the as-implanted state. In a narrow dose window in between, controlled exfoliation could be obtained upon post-implantation annealing only. Cross-sectional transmission electron microscopy (XTEM) of the implanted ZnO samples showed that a large number of nanovoids were formed within the implantation-induced damage band. These nanovoids served as precursors for the formation of microcracks leading to the exfoliation of ZnO wafer surfaces. In addition to the nanovoids, elongated nanocolumns perpendicular to the ZnO wafer surfaces were also observed. These nanocolumns showed diameters of up to 10 nm and lengths of up to 500 nm. The nanocolumns were found in the ZnO wafer even well beyond the projected range of hydrogen ions.


1993 ◽  
Vol 322 ◽  
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell

AbstractA systematic study of the structure-mechanical properties relationship is reported for MoSi2-SiC nanolayer composites. Alternating layers of MoSi2 and SiC were synthesized by DCmagnetron and if-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures. Nanoindentation was employed to characterize the mechanical response as a function of the structural changes. As-sputtered material exhibits amorphous structures in both types of layers and has a hardness of 11GPa and a modulus of 217GPa. Subsequent heat treatment induces crystallization of MoSi2 to form the C40 structure at 500°C and SiC to form the a structure at 700°C. The crystallization process is directly responsible for the hardness and modulus increase in the multilayers. A hardness of 24GPa and a modulus of 340GPa can be achieved through crystallizing both MoSi2 and SiC layers. Annealing at 900°C for 2h causes the transformation of MoSi2 into the Cllb structure, as well as spheroidization of the layering to form a nanocrystalline equiaxed microstructure. A slight degradation in hardness but not in modulus is observed accompanying the layer break-down.


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