Millisecond laser-induced damage process of (001) silicon wafer

The use of lasers for surface annealing, heating and/or damage has become a routine practice in the study of materials. Lasers have been closely looked at as an annealing technique for silicon and other semiconductors. They allow for local heating from a beam which can be focused and tuned to different wavelengths for specific tasks. Pulsed dye lasers allow for short, quick bursts which can allow the sample to be rapidly heated and quenched. This short, rapid heating period may be important for cases where diffusion of impurities or dopants may not be desirable.At Northwestern University, a Candela SLL - 250 pulsed dye laser, with a maximum power of 1 Joule/pulse over 350 - 400 nanoseconds, has been set up in conjunction with a Hitachi UHV-H9000 transmission electron microscope. The laser beam is introduced into the surface science chamber through a series of mirrors, a focusing lens and a six inch quartz window.

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Interlayer mixing in GaAs/AlxGa1-xAs heterostructures as a result of Se+ ion implantation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106600 ◽

1988 ◽

Vol 46 ◽

pp. 908-909

Author(s):

E.G. Bithell ◽

W.M. Stobbs

Keyword(s):

Ion Implantation ◽

Diffusion Coefficients ◽

Dark Field ◽

Atomic Mass ◽

Composition Profile ◽

Semiconductor Heterostructures ◽

Transmission Electron ◽

Microscope Images ◽

Damage Process ◽

Electron Energy Loss

It is well known that the microstructural consequences of the ion implantation of semiconductor heterostructures can be severe: amorphisation of the damaged region is possible, and layer intermixing can result both from the original damage process and from the enhancement of the diffusion coefficients for the constituents of the original composition profile. A very large number of variables are involved (the atomic mass of the target, the mass and energy of the implant species, the flux and the total dose, the substrate temperature etc.) so that experimental data are needed despite the existence of relatively well developed models for the implantation process. A major difficulty is that conventional techniques (e.g. electron energy loss spectroscopy) have inadequate resolution for the quantification of any changes in the composition profile of fine scale multilayers. However we have demonstrated that the measurement of 002 dark field intensities in transmission electron microscope images of GaAs / AlxGa1_xAs heterostructures can allow the measurement of the local Al / Ga ratio.

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Anisotropic radiation damage of potassium tetracyano platinate (KCP)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109100 ◽

1978 ◽

Vol 36 (1) ◽

pp. 392-393

Author(s):

N. Uyeda ◽

E. J. Kirkland ◽

B. M. Siegel

Keyword(s):

Electron Diffraction ◽

Radiation Damage ◽

Structural Changes ◽

High Resolution Electron Microscopy ◽

Radiation Sensitivity ◽

Resolution Electron ◽

Damage Process ◽

Diffraction Patterns ◽

Fading Rate

The direct observation of structural change by high resolution electron microscopy will be essential for the better understanding of the damage process and its mechanism. However, this approach still involves some difficulty in quantitative interpretation mostly being due to the quality of obtained images. Electron diffraction, using crystalline specimens, has been the method most frequently applied to obtain a comparison of radiation sensitivity of various materials on the quantitative base. If a series of single crystal patterns are obtained the fading rate of reflections during the damage process give good comparative measures. The electron diffraction patterns also render useful information concerning the structural changes in the crystal. In the present work, the radiation damage of potassium tetracyano-platinate was dealt with on the basis two dimensional observation of fading rates of diffraction spots. KCP is known as an ionic crystal which possesses “one dimensional” electronic properties and it would be of great interest to know if radiation damage proceeds in a strongly asymmetric manner.

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