scholarly journals The Formation of Amorphous Silicon by Light Ion Damage

1985 ◽  
Vol 45 ◽  
Author(s):  
Y. Shih ◽  
J. Washburn ◽  
E.R. Weber ◽  
R. Gronsky
Keyword(s):  
Ion Implantation ◽  
Amorphous Silicon ◽  
Point Defect ◽  
Point Defects ◽  
Liquid Nitrogen Temperature ◽  
Paramagnetic Resonance ◽  
High Resolution Tem ◽  
Different Temperatures ◽  
Boron Ions ◽  
Point Defect Clusters

ABSTRACTA model for formation of amorphous silicon by light ion implantation is proposed. It is suggested that accumulation of point defects and/or complexes is required at the initial stage of the amorphization process. Amorphous zones can only form at the end of incoming light ion tracks when the pre-accumulated concentration of point defects reaches a critical value. Depending on the uniformity of the point defect distribution, two possibilities for the second stage of amorphization are suggested when ion implantation is performed at different temperatures.Silicon wafers implanted with boron ions below and above the critical amorphization dose at various temperatures have been investigated using cross section specimens in high resolution TEM. Complementary analyses of these specimens by Electron Paramagnetic Resonance have revealed the presence of dangling bonds in amorphous zones and point defect clusters. Extrinsic stacking faults with 1/3 <111> displacements and other smaller distortions with 1/x<111> displacements were also found to result from the amorphization process. Liquid nitrogen temperature was found to be necessary to cause complete amorphization of silicon by boron ion implantation.

Amorphization of Silicon by Boron Ion Implantation

1986 ◽  
Vol 71 ◽  
Author(s):  
Y. Shih ◽  
J. Washburn ◽  
R. Gronsky ◽  
E.R. Weber
Keyword(s):  
Ion Implantation ◽  
Amorphous Silicon ◽  
Point Defects ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Critical Energy ◽  
High Energy ◽  
Dose Rates ◽  
Initial Stage ◽  
Boron Ions

AbstractAmorphization of silicon due to implantation of boron ions which is the lightest element used for I.C. fabrication processes, has been systematically studied for various temperatures, voltages and dose rates. A model for formation of amorphous silicon by light ion implantation is proposed. It is suggested that accumulation of point defects and/or clusters is required at the initial stage of amorphization process. Diinterstitial -divacancy pairs are suggested to be the embryos of amorphous zones formed during implantation at room temperature. Out -diffusion of highly mobile interstitials during amorphization is thought to explain differences in the critical energy for amorphization with low and high energy implantation at liquid nitrogen temperature.

X-Ray Diffuse Scattering Investigation of Defects in Ion Implanted and Annealed Silicon

1998 ◽  
Vol 524 ◽  
Author(s):  
C. H. Chang ◽  
U. Beck ◽  
T. H. Metzger ◽  
J. R. Patel
Keyword(s):  
Ion Implantation ◽  
Point Defect ◽  
Point Defects ◽  
Diffuse Scattering ◽  
Grazing Incidence ◽  
X Rays ◽  
Scattered Intensity ◽  
X Ray ◽  
Defect Clusters ◽  
Point Defect Clusters

ABSTRACTTo characterize the point defects and point defect clusters introduced by ion implantation and annealing, we have used grazing incidence x-rays to measure the diffuse scattering in the tails of Bragg peaks (Huang Scattering). An analysis of the diffuse scattered intensity will allow us to characterize the nature of point defects or defect clusters introduced by ion implantation. We have also observed unexpected satellite peaks in the diffuse scattered tails. Possible causes for the occurrence of the peaks will be discussed.

Depth Profile Of Point Defects In Ion Implanted n+p and p+n Junctions Formed By 450°C Post-Implantation Annealing And Impact Of Defects On Junction Characteristics

1996 ◽  
Vol 442 ◽  
Author(s):  
Mauricio Massazumi Oka ◽  
Akira Nakada ◽  
Yukio Tamai ◽  
Kei Kanemoto ◽  
Tadashi Shibata ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Point Defects ◽  
Substrate Type ◽  
Leakage Currents ◽  
Defect Clusters ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Point Defect Clusters ◽  
Ion Species ◽  
Post Implantation

AbstractIt is shown that defects generated by ion implantation, remaining after annealing at low temperature, are deep-distributed in the bulk silicon and their amount is demonstrated to be function of the substrate type and the implanted ion species. The confirmation that defects penetrate deeply into the silicon is made by a new method that consists in damaging by ion implantation a previously formed pn junction that shows very low leakage current and has a deep junction. It is proposed that the dopants in the substrate act as nucleation centers for the formation of point defect clusters and that these clusters actually degrade the junction. It was found that point defects penetrate much more deeply in p+n junctions than in n+p junctions. It was also found that BF2+ introduces much more defects into the silicon than As+, owing to the presence of fluorine. The leakage currents at 5 V of n+p and p+n diodes made by implantation of P+ and B+, respectively, could be lowered by one to two orders of magnitude with respect to values obtained by implantation of As+ and BF2+ because the former ones produce less defects than the latter.

The Microstructual Characterization of Boron Ion Implanted Silicon During Amorphization Process

1985 ◽  
Vol 43 ◽  
pp. 302-303 ◽  
Author(s):  
Yih-Cheng Shih ◽  
Jack Washburn
Keyword(s):  
High Resolution ◽  
Ion Implantation ◽  
Cross Section ◽  
Heavy Ion ◽  
Transformation Process ◽  
Paramagnetic Resonance ◽  
Dose Rates ◽  
High Resolution Images ◽  
Boron Ions

Two amorphization models, heterogeneous and homogeneous nucleation have been used to describe heavy ion implantation at low temperature and light ion implantation at high temperature by many authors. However, the amorphization mechanism for light ion damage is still unclear. Cross section views of the amorphous-crystalline transition region afford a continuous picture of the crystalline to amorphous transformation process. In this work, high resolution cross-section TEM has been used to clarify the amorphization mechanism for silicon implanted with Boron ions at various temperatures and dose rates.A cross section view is shown in Fig. 1, of silicon implanted with 1x1016/cm2 Boron ions at room temperature and 80 KeV energy. It shows that small spots first gather around near the depth of peak damage (∼2300A below the surface). High resolution images of these spots reveals that they are damage zones losing periodic atom arrangement (Fig. 2). The Electron Paramagnetic Resonance Spectrum from the same specimen contains an isotropic amorphous peak.

Optimization of Ion Implantation processes for 4H-SiC DIMOSFET

MRS Advances ◽  
2016 ◽  
Vol 1 (55) ◽  
pp. 3673-3678 ◽  
Author(s):  
N. Piluso ◽  
E. Fontana ◽  
M.A. Di Stefano ◽  
G. Litrico ◽  
S. Privitera ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Point Defects ◽  
Electrical Characteristic ◽  
Implantation Dose ◽  
Annealing Process ◽  
Considerable Improvement ◽  
Electrical Characteristics ◽  
Different Temperatures ◽  
Implantation Process

AbstractIn this paper the defects generated by ion implantation in 4H-SiC DIMOSFET (Double Implanted MOSFETs), and their evolution after annealing process, have been studied in detail. The point defects generated by the source or body implantation process have been detected by micro-photoluminescence (µPL) and the effect of these defects on the electrical characteristics of the DIMOSFET has been studied. The role of the annealing process has been carefully investigated by using different temperatures. It appears fundamental for the restoring of the crystal damage. The effect of the ion implantation dose has been investigated as well. By reducing the source ion implanted dose a large decrease of point defects has been detected and a considerable improvement of the electrical characteristic of the DIMOSFET has been observed.

Ion Implantation of Boron in Diamond

1988 ◽  
Vol 128 ◽  
Author(s):  
G. S. Sandhu ◽  
M. L. Swanson ◽  
W. K. Chu
Keyword(s):  
Optical Absorption ◽  
Ion Implantation ◽  
Natural Diamond ◽  
Liquid Nitrogen Temperature ◽  
Type Ii ◽  
Electrical Measurements ◽  
Boron Ions ◽  
Dopant Atoms ◽  
P Type ◽  
Diamond Type

ABSTRACTIt has been a challenge to inject dopant atoms onto diamond lattice sites by ion implantation, because of the complications of ion damage and defect clustering during annealing. We re-investigated this topic by implanting boron ions into an insulating natural diamond ( type II-A ) which was predamaged by carbon ion implantation. Both of the implantations were performed at liquid nitrogen temperature. The amount of pre-damage was adjusted to produce enough vacancies and interstitials in diamond to promote boron substitutionality during subsequent annealing. Samples were characterized by optical absorption and electrical measurements. It was found that optical absorption of the implanted samples strongly depends on the post implant annealing sequence. The activation energies obtained from electrical measurements match very closely to those due to boron atoms in natural p-type diamonds. Photoconductivity measurements showed that the fraction of remaining electrically active radiation defects in the implanted and annealed samples depends on the relative fluences of boron and carbon.

Ion Implantation-Induced Amortization of Ceramic Oxides

1989 ◽  
Vol 157 ◽  
Author(s):  
D.F. Pedraza
Keyword(s):  
Free Energy ◽  
Ion Implantation ◽  
Point Defect ◽  
Point Defects ◽  
Amorphous State ◽  
Amorphous Solid ◽  
Rate Theory ◽  
Theory Approach ◽  
Ceramic Oxides ◽  
Radiation Induced

ABSTRACTA mechanism of amorphization by ion implantation in ceramic oxides is studied using a rate theory approach. It is proposed that the production of highly localized lattice distortions causes lattice destabilization and the ensuing transition to the amorphous state. These distortions can be caused by a large point defect buildup. It is argued that point defect retention occurs because of the impossibility of producing antisite defects. It is proposed that point defects on each sublattice can shield or trap point defects on the other sublattice. Similarly, metallic impurities may shield oxygen vacancies or trap oxygen interstitial ions, preventing anion Frenkel pairs from recombining. These effects are modeled in a-alumina for low temperature implantations (e.g., around 78 K), where point defects are immobile. It is shown that, at these temperatures, recombination is strongly hindered by the radiation-induced point defects themselves, rather than by the implanted impurities. The high point defect concentration attained by this mechanism is sufficient to raise the free energy of the crystal above the free energy of the amorphous solid.

Exafs Studies of Ion Implanted Bismuth

1984 ◽  
Vol 41 ◽  
Author(s):  
E. M. Kunoff ◽  
M. S. Dresselhaus ◽  
Y. H. Kao
Keyword(s):  
Ion Implantation ◽  
Point Defects ◽  
Nearest Neighbor ◽  
Local Environment ◽  
Sample Surface ◽  
High Energy ◽  
Synchrotron Source ◽  
Different Temperatures ◽  
Total Fluence ◽  
Nearest Neighbor Distances

AbstractMagnetorefiection and preliminary Rutherford Backscattering channeling experiments indicate that point defects induced in the bismuth lattice by ion implantation are largely annealed out during the implantation process due to its low melting temperature of 271.3°C. These experiments also show that the implanted ions cause long range strains in the crystal. Single crystal bismuth samples have been implanted at low temperatures (from 273°K down to 77°K) with 75 As to a total fluence of 5 × 1016/cm2 at energies ranging from 50 keV to 200 keV to yield an approximately constant arsenic profile from the sample surface to a depth of 625 Å. To study the local environment of the implanted As ions, EXAFS measurements have been made at the Cornell High Energy Synchrotron Source (CHESS). From these data, we obtain a comparison of the As nearest neighbor distances in samples implanted at different temperatures. We discuss the effect of sample temperature during implantation on these properties. This work represents the first use of EXAFS to characterize annealing of implantation-induced lattice defects during the process of ion implantation.

Study of point defects in as-grown and annealed bismuth germanate single crystals

2005 ◽  
Vol 38 (3) ◽  
pp. 448-454 ◽  
Author(s):  
G. Bhagavannarayana ◽  
A. Choubey ◽  
Yu. V. Shubin ◽  
Krishan Lal
Keyword(s):  
Point Defect ◽  
Single Crystals ◽  
Point Defects ◽  
Bismuth Germanate ◽  
Cluster Radius ◽  
X Ray ◽  
Defect Clusters ◽  
X Ray Scattering ◽  
Point Defect Clusters ◽  
Ray Scattering

Point defects and their clusters in bismuth germanate single crystals free from grain boundaries and having low density of dislocations were studied by high-resolution diffuse X-ray scattering measurements. Differences in defects in the colourless crystals (type A) and the crystals having yellow tinge (type B), which were grown with different raw materials, were investigated. In addition, interesting differences in defect structures in specimens from different regions of the same boule were investigated. Specimens with diffracting surfaces along (111), (112) and (100) planes were studied. A multicrystal X-ray diffractometer employing a well collimated and highly monochromated Mo Kα1 beam and set in (+,−,−,+) configuration was employed. The diffraction curves of all the samples were quite narrow with half-widths in the range 7–11 arcsec, which are close to the theoretically expected values, if instrumental broadenings are taken into account. The observed distribution of diffuse X-ray scattering (DXS) intensity showed that not all the point defects are isolated but a significant fraction are agglomerated into clusters. Experimental data of DXS intensity were analysed by using a phenomenological model for a small concentration of dislocation loops wherein the point defects are loosely clustered with weak interactions among them. From this analysis, the cluster radius R cl, cluster volume A cl, the number of point defects within a cluster N cl and the relative concentration of the point-defect clusters among the samples were estimated. It was observed that cluster sizes do not vary from sample to sample. However, it was found that the concentration of clusters is approximately twice in the coloured sample compared with that of the colourless sample from the same boule. Annealing of the crystals at 1273 K produced an increase in point-defect clusters by a factor of ∼200. It was accompanied by a reduction in volume of clusters by a factor of ∼0.14.

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