Surface Studies of Laser Annealed Semiconductors

1982 ◽  
Vol 13 ◽  
Author(s):  
D. M. Zehner ◽  
C. W. White
Keyword(s):  
Single Crystals ◽  
Laser Irradiation ◽  
Ruby Laser ◽  
Ultrahigh Vacuum ◽  
Surface Structures ◽  
Pulse Irradiation ◽  
Surface Studies ◽  
Rapid Cooling ◽  
Before And After ◽  
Irradiation Process

ABSTRACTThe surface regions of semiconductor single crystals have been examined following laserannealing in an ultrahigh vacuum environment with the output of a pulsed ruby laser. Atomically clean surfaces with impurity levels below 0.1% of a monolayer can be produced by multiple pulse irradiation. Ordered surface structures are produced on low index oriented crystals as well as crystals slightly misoriented. Metastable surface structures exhibiting (l×1) LEED patterns have been produced on (111) orientations and are believed to be a consequence of the rapid cooling rates of 109 degs/sec achieved with the laser irradiation process. The surface and subsurface regions of ion-implanted Si crystals have been examined both before and after laser irradiation and results obtained from Si samples implanted with As are discussed.

Silicon Bipolar Transistors Fabricated using Ion Implantation and Laser Annealing

1980 ◽  
Vol 1 ◽  
Author(s):  
Nobuyoshi Natsuaki ◽  
Takao Miyazaki ◽  
Makoto Ohkura ◽  
Toru Nakamura ◽  
Masao Tamura ◽  
...  
Keyword(s):  
Low Temperature ◽  
Laser Pulse ◽  
Laser Irradiation ◽  
Ruby Laser ◽  
Laser Annealing ◽  
Bipolar Transistors ◽  
Pulse Irradiation ◽  
Irradiation Effects ◽  
Furnace Annealing ◽  
Temperature Furnace

ABSTRACTBipolar transistors with laser annealed base and emitter, as well as those with furnace annealed base and laser annealed emitter, have been successfully fabricated using Q-switched ruby laser pulse irradiation. The performance of laser asannealed transistors is rather poor. However, it can be improved, to some extent, by relatively low temperature furnace annealing after laser irradiation. DC and RF characteristics of laser annealed transistors are presented in conjunction with laser irradiation effects on the characteristics of conventionally fabricated transistors.

Studies of Laser Annealed GaAs (100), (110) and (111) Surfaces

1981 ◽  
Vol 4 ◽  
Author(s):  
D. M. Zehner ◽  
C. W. White ◽  
B. R. Appleton ◽  
G. W. Ownby
Keyword(s):  
Single Crystals ◽  
Laser Irradiation ◽  
Crystal Orientation ◽  
Ruby Laser ◽  
Surface Layers ◽  
Auger Transition ◽  
Subsurface Region ◽  
Outermost Surface

ABSTRACTThe surface regions of (100), (110) and (111) oriented single crystals of GaAs have been investigated by the combine techniques of LEED, AES and RBS subsequent to their irradiation in UHV with the output of a Q–switched, ruby laser (0.15−0.8 J/cm2, 15 × 10−9 sec). Clean surfaces, as determined by AES, were obtained after Ar+ sputtering followed by laser irradiation. LEED observations indicate that the degree of disorder in the outermost surface layers remaining after irradiation depends on the crystal orientation. Although the relative intensities of Ga and As Auger transitions in spectra obtained from sputtered and laser annealed surfaces are similar, the differences in lineshape in these spectra of the M2,3M4,5M4,5 Ga Auger transition indicate that in the laser annealed case there are local regions which are nonstoichiometric. These observations are confirmed by RBS results, and this technique has been used to determine the stoichiometry and to characterize the damage in the subsurface region for all orientations.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

A New Hafnium-Beryllium System Prioduced by Ion Implantation and Annealing Techniques

1983 ◽  
Vol 27 ◽  
Author(s):  
J.C. Soares ◽  
A.A. Melo ◽  
M.F. DA Silva ◽  
E.J. Alves ◽  
K. Freitag ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystals ◽  
Room Temperature ◽  
Low Dose ◽  
Correlation Method ◽  
High Dose ◽  
Tetrahedral Sites ◽  
Time Differential ◽  
Before And After ◽  
Beryllium Foil

ABSTRACTLow and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation of beryllium commercial foils and single crystals. These samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling techniques. A new metastable system has been discovered in TDPAC-measurements in a low dose hafnium implanted beryllium foil annealed at 500°C. Channeling measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from the previous position occupied after implantation. The formation of this system is connected with the redistribution of oxygen in a thin layer under the surface. This effect does not take place precisely at the same temperature in foils and in single crystals.

Laser irradiation of nickel single crystals

1980 ◽  
Vol 37 (4) ◽  
pp. 385-387 ◽  
Author(s):  
L. Buene ◽  
J. M. Poate ◽  
D. C. Jacobson ◽  
C. W. Draper ◽  
J. K. Hirvonen
Keyword(s):  
Single Crystals ◽  
Laser Irradiation
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