Effect of beam current on defect formation by high-temperature implantation of Mg ions into GaN

2022 ◽  
Author(s):  
Yuta ITOH ◽  
Hirotaka Watanabe ◽  
Yuto Ando ◽  
Emi Kano ◽  
Manato Deki ◽  
...  
Keyword(s):  
High Temperature ◽  
Ion Implantation ◽  
Defect Formation ◽  
Vacancy Concentration ◽  
Beam Current ◽  
Dislocation Loops ◽  
Transmission Electron Microscopy Analysis ◽  
Scanning Transmission ◽  
Electron Microscopy Analysis ◽  
Beam Currents

Abstract We evaluated the beam current dependence of defect formation during Mg ion implantation into GaN at a high temperature of 1100℃ with two beam currents. Photoluminescence spectra suggested that low-beam-current ion implantation reduced the vacancy concentration and activated Mg to a greater extent. Moreover, scanning transmission electron microscopy analysis showed that low-beam-current implantation reduced the density of Mg segregation defects with inactive Mg and increased the number of intrinsic dislocation loops, suggesting a decrease in the density of Ga and N vacancies. The formation of these defects depended on beam current, which is an important parameter for defect suppression.

Tem Observation Of Grown-In Defects In CZ-Si Crystals And Their Secco Etching Properties

1996 ◽  
Vol 442 ◽  
Author(s):  
Masahiro Kato ◽  
Hiroshi Takeno ◽  
Yutaka Kitagawara
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Defect Formation ◽  
Flow Patterns ◽  
Dislocation Loops ◽  
Formation Factor ◽  
Total Size ◽  
Laser Scattering ◽  
Temperature Oxidation ◽  
Defect Species

AbstractGrown-in defects detected by IR laser scattering tomography (LSTDs) in Czochralski-grown Si crystals were identified by transmission electron microscopy (TEM) with a special defect positioning technique. The basic structure of the LSTD was revealed to be a composite of two or three incomplete octahedral voids with the 100–300nm total size. The TEM images of the defect showed existence of 2∼4nm-thick walls surrounding the voids. These thin-walls are considered to be made of oxide, SiOx. These LSTDs are indeed dominant grown-in defect species in most of the commercial CZ-Si walers. The LSTD after 1200°C oxidation was also observed by TEM. The resulting image shows that the defect changed from void to filled oxide precipitate by the high temperature heat treatment. On the other hand, in very slowly pulled crystals with ∼0.4mm/min rate, interstitial type dislocation loops were observed as major defect species. Non-agitated Secco etching of these grown-in defects delineates “flow patterns” (FPs) or pits without the flow patterns. The FP forming property is shown to disappear by oxidation at temperature above 1150°C, while the defect itself remains stable. This implies that the grown-in defects lose their chemical properties to form FPs by the high-temperature oxidation. It is further revealed that the grown-in defects, which once lost the FP forming property by the high-temperature oxidation, can form FPs again by an intentional Cu contamination. Thus a possible FP formation factor is Cu decoration at the grown-in defect site. Defect formation model of the as-grown twin-type LSTD is also proposed.

The Influence of the Initial Supersaturation of Si Interstitial Atoms on the Relative Thermal Stability of Dislocation Loops in Silicon

2000 ◽  
Vol 610 ◽  
Author(s):  
F. Cristiano ◽  
B. Colombeau ◽  
B. de Mauduit ◽  
F. Giles ◽  
M. Omri ◽  
...  
Keyword(s):  
Relative Stability ◽  
Thermal Evolution ◽  
Dislocation Loops ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Interstitial Atoms ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Implantation Process ◽  
Formation Energies

AbstractIn this work, we have studied the relative stability of perfect (PDLs) and faulted (FDLs) dislocation loops formed during annealing of preamorphised silicon. In particular, we have investigated the effect of the initial supersaturation of Si interstitial atoms (Si(int)s) created by the implantation process on their thermal evolution. Transmission Electron Microscopy analysis shows that in samples with a low Si interstitial supersaturation, FDLs are the dominant defects while PDLs appear as the most stable defects in highly supersaturated samples. We have calculated the formation energies of both types of dislocation loops and found that, for defects of the same size, FDLs are more energetically stable than PDLs, if their diameter is smaller than 80 nm and viceversa. The application of these calculations to the samples studied in this work indicates that a direct correspondence exists between the formation energy of the two defect families and the number of atoms bound to them. Moreover, we have shown that the relative stability of FDLs and PDLs depends on the initial supersaturation of Si(int)s created during the implantation process.

Low Angle Annular Dark Field Scanning Transmission Electron Microscopy Analysis of Phase Change Material

2021 ◽  
Author(s):  
J. Li ◽  
K. Brew ◽  
K. Cheng ◽  
V. Chan ◽  
N. Arnold ◽  
...  
Keyword(s):  
Rapid Development ◽  
Dark Field ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Before And After ◽  
Annular Dark Field ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Change Material

Abstract The continuously growing demands in high-density memories drive the rapid development of advanced memory technologies. In this work, we investigate the mushroom type PCM cells based on Ge2Sb2Te5 at nanoscale by low angle annular dark field (LAADF) STEM imaging technique as well as energy dispersive X-ray spectroscopy (EDX) to study the changes in microstructure and elemental distributions in PCM mushroom cells before and after SET and RESET conditions. We describe the microscope settings used for LAADF image formation to reveal the amorphous dome in RESET device and discuss the application example in failure analysis of PCM test device.

scholarly journals (Al,Mg)3La: a new phase in the Mg–Al–La system

2018 ◽  
Vol 74 (4) ◽  
pp. 370-375 ◽  
Author(s):  
Charlotte Wong ◽  
Mark J. Styles ◽  
Suming Zhu ◽  
Dong Qiu ◽  
Stuart D. McDonald ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Dark Field ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electron Microscopy Analysis

During an investigation of the Mg-rich end of the Mg–Al–La system, a new ternary phase with the composition of (Al,Mg)3La was identified. The crystal structure of this phase was determined by conventional X-ray powder diffraction and transmission electron microscopy analysis and refined using high-resolution X-ray powder diffraction. The (Al,Mg)3La phase is found to have an orthorhombic structure with a space group of C2221 and lattice parameters of a = 4.3365 (1) Å, b = 18.8674 (4) Å and c = 4.4242 (1) Å, which is distinctly different from the binary Al3La phase (P63/mmc). The resolved structure of the (Al,Mg)3La phase is further verified by high-angle annular dark-field scanning transmission electron microscopy.

The Use of Negative Ions in Ion Implantation with Tandem High Energy Accelerators

1993 ◽  
Vol 316 ◽  
Author(s):  
John P. O'Connor ◽  
Nobuhiro Tokoro
Keyword(s):  
Ion Implantation ◽  
Negative Ions ◽  
Beam Current ◽  
High Energy ◽  
Low Energy ◽  
Energy Beam ◽  
System Changes ◽  
Low Energies ◽  
Beam Currents ◽  
Medium Dose

ABSTRACTSince the introduction of the G1500 ion implanter, the use of tandem accelerators in production ion implantation systems has become well established. However, the beam currents which are attainable at present at low energies (< 200 keV) are suitable for only low and low-end medium dose implants. An approach to increase low energy beam currents in d.c. tandem accelerators is presented. Specifically, the use of negative ions which have been generated in the injector are transported to the end station and implanted into the wafers. In this work, beam current measurements performed using the G1500 system are presented for the typical semiconductor dopants. System changes which are necessary to accomplish implants with negative ions are discussed. A comparison of sheet resistances and uniformities measured with both positive and negative ions at the same energy and from the same G1500 system are presented. SIMS profile measurements of implants with both positive and negative ions at the same energy are also presented.

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