Appendix IV: Masses in Atomic Mass Units for Neutral Atoms of Stable Nuclides and a Few Unstable Nuclides

Effects of Ion Beam Milling on Surface Topography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070862 ◽

1973 ◽

Vol 31 ◽

pp. 84-85

Author(s):

P.G. Pawar ◽

P. Duhamel ◽

G.W. Monk

Keyword(s):

Surface Topography ◽

Ion Beam ◽

Solid Material ◽

Beam Current ◽

Atomic Mass ◽

Micro Milling ◽

Ion Milling ◽

Controlled Atmospheres ◽

Milling Operations ◽

Sufficient Energy

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.

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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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