Auger electron spectroscopy at high spatial resolution and nA primary beam currents

Experimental data about the dependence of the Auger signal from crystalline samples on the primary beam direction are presented and discussed. It is shown that, for Auger electrons and elastically and inelastically backscattered electrons, maxima of the signal in its dependence on the polar and azimuth angles of the primary beam (in polar and azimuth profiles, respectively) appear when the primary beam is parallel either to one of the close-packed rows of atoms or to one of the densely packed atomic planes in the sample. This indicates that the diffraction of the primary electron beam is responsible for the dependence mentioned above. Mechanisms proposed for simple explanation of this dependence (channeling and forward focusing of primary electrons) are presented and results of their application are discussed. It is shown that both those mechanisms play an important role in the creation of the Auger signal contrast. The possibilities and limitations of the application of polar and azimuth Auger emission profiles in the determination of the surface layer crystalline structure (directional Auger electron spectroscopy — DAES) are presented and discussed. It is shown that the thickness of the investigated surface layer can be decreased up to a few monolayers. Results obtained with DAES are similar to those provided by X-ray photoelectron diffraction (XPD) and Auger electron diffraction (AED), but the DAES experimental equipment is simple and inexpensive and measurements are fast. Finally, experimental systems for DAES are described and examples of DAES applications are presented.

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Auger electron spectroscopy at nanometer resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132017 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1476-1477

Author(s):

Gary G. Hembree

Keyword(s):

Auger Electron Spectroscopy ◽

Spatial Resolution ◽

Electron Spectroscopy ◽

Auger Electron ◽

Production Efficiency ◽

Incident Beam ◽

Atomic Scale ◽

Objective Lens ◽

Auger Electrons ◽

Thin Samples

Auger electron spectroscopy (AES) is a surface sensitive microanalytical technique. Auger electrons are only detected from the top few atomic layers due to their very small inelastic mean free paths. The lateral spatial resolution of AES of thin samples is dominated by the excitation beam profile. Thin samples are defined as having a thickness which is much smaller than the back-scattered electron range at the incident beam energy. Utilizing high current density nanometer-sized probes available in field emission gun STEMs, AES signals extracted from sample regions as small as a few atoms should be detectable. However, the extremely low production efficiency for Auger electrons makes this atomic scale resolution difficult to achieve in practice.We have achieved nanometer spatial resolution AES in our modified Vacuum Generators HB-501S. In this instrument secondary electrons emitted from either surface of the sample are efficiently collected using the collimating properties of the objective lens field, a sample bias potential and additional solenoidal focusing coils.

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Variations of surface roughness for deposition of Co-sputtered-ZnO(002) by Auger electron spectroscopy and surface magneto-optic Faraday effect

The European Physical Journal Applied Physics ◽

10.1051/epjap/2010100312 ◽

2011 ◽

Vol 53 (2) ◽

pp. 21501 ◽

Cited By ~ 3

Author(s):

Y.-C. Chang ◽

C.-W. Su ◽

S.-C. Chang ◽

Y.-H. Lee

Keyword(s):

Surface Roughness ◽

Auger Electron Spectroscopy ◽

Electron Spectroscopy ◽

Auger Electron ◽

Faraday Effect ◽

Magneto Optic

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The formation of low temperature Cu3Si in Ag(Cu)/Si structure upon annealing and its effects on adhesion and resistivity

MRS Proceedings ◽

10.1557/proc-766-e3.15 ◽

2003 ◽

Vol 766 ◽

Cited By ~ 3

Author(s):

Sungjin Hong ◽

Seob Lee ◽

Yeonkyu Ko ◽

Jaegab Lee

Keyword(s):

Low Temperature ◽

Auger Electron Spectroscopy ◽

Electron Spectroscopy ◽

Auger Electron ◽

Si Substrate ◽

Copper Silicide ◽

Alloy Films ◽

Cu Alloy ◽

Cu Film ◽

Rapid Drop

AbstractThe annealing of Ag(40 at.% Cu) alloy films deposited on a Si substrate at 200 – 800 oC in vacuum has been conducted to investigate the formation of Cu3Si at the Ag-Si interface and its effects on adhesion and resistivity of Ag(Cu)/Si structure. Auger electron spectroscopy(AES) analysis showed that annealing at 200°C allowed a diffusion of Cu to the Si surface, leading to the significant reduction in Cu concentration in Ag(Cu) film and thus causing a rapid drop in resistivity. In addition, the segregated Cu to the Si surface reacts with Si, forming a continuous copper silicide at the Ag(Cu)/Si interface, which can contribute to an enhanced adhesion of Ag(Cu)/Si annealed at 200 oC. However, as the temperature increases above 300°C, the adhesion tends to decrease, which may be attributed to the agglomeration of copper silicide beginning at around 300°C.

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