Influence of laser parameters on the detection efficiency of sputtered neutrals mass spectrometry based on non-resonant multiphoton ionization

Kaesdorf, S.; Hartmann, Maximilian; Schröder, H.; Kompa, K. L.

doi:10.1016/0168-1176(92)80042-y

Cited by 30 publications

(8 citation statements)

References 33 publications

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“…It should be noted that the dimer formation is matrix dependent. It has to be considered, however, in the regime of absolute saturation dimers may be disregarded [7].…”

Section: Further Resultsmentioning

confidence: 99%

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Surface Analysis by Laser Ionization

Schröder

Wagner

Kaesdorf

et al. 1993

Ber Bunsenges Phys Chem

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The accuracy in measuring the phase velocity with the acoustic microscope is about 0.1 '70 and thus comparable for both methods. However, since the pulsed laser technique is broadband a much higher information content is obtained in the case of dispersion, e.g. in layered systems. This information, however, is averaged over a macroscopic area. Ultimate Limit of Broadband SAW SpectroscopyThe ultimate limit of the pulsed laser SAW method is given by the capability to focus the laser radiation onto the surface. The size of the laser spot or the width of the line focus is limited by the wavelength of the light. If it is, for example, 0.5 pm, the shortest wavelength in the SAW pulse would be about 1 pm, which corresponds to several gigahertz. Thus the pulsed laser method may approach the lower frequency limit of Brillouin scattering.A bandwidth limitation by the laser pulse duration can be completely avoided by choosing a pulse duration in the picosecond range. The penetration depth of light into the solid can also be much smaller than the width of the line focus and therefore is not a limiting factor for the bandwidth in the ideal case. As a consequence of the extremely high absorption coefficients observed in some solids (lo5 -lo6 cm-'), a much higher frequency can be achieved for the excitation of longitudinal bulk phonons, where 60GHz has been reached [30].

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“…It should be noted that the dimer formation is matrix dependent. It has to be considered, however, in the regime of absolute saturation dimers may be disregarded [7].…”

Section: Further Resultsmentioning

confidence: 99%

“…Recently, we have discussed the influence of laser parameters on the detection efficiency of SNMS based on nonresonant multiphoton ionization [7]. In this article we wish to discuss a new method, how to quantify laser ionization.…”

Section: Quantification Of Laser Ionizationmentioning

confidence: 99%

Surface Analysis by Laser Ionization

Schröder

Wagner

Kaesdorf

et al. 1993

Ber Bunsenges Phys Chem

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“…(1), D is the implanted Zn dose (cm 22 ), S is the Zn signal at each point, n is the number of points in the profile, d is the crater depth (cm), and S is the integrated Zn signal. 13 This is certainly true for sub-picosecond pulses. 2, the determined Zn concentration and the Zn UHIPI signal are arbitrarily chosen to scale together.…”

Section: ͓Zn͔mentioning

confidence: 97%

Characterization of InGaAsP materials by ultrahigh intensity post-ionization mass spectrometry: Relative sensitivity factors for zinc versus bulk constituents

1996

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The first relative sensitivity factors (RSF) for detecting the major and dopant elements of optical materials by ultrahigh intensity post-ionization (UHIPI) mass spectrometry are determined. The post-ionization is performed using a single laser wavelength with intensities greater than 10 14 W͞cm 2 . Zn-implanted InP and In 0.4 Ga 0.1 As 0.3 P 0.2 are used to investigate the photoionization of sputtered atoms and molecules. Under optimal conditions, the UHIPI RSF's for atomic singly charged In, Ga, and Zn are nearly equal; that is, the ratio of UHIPI signals is equal to the concentration ratio. In principle, no standards are needed for quantitative analysis. Arsenic and P, with higher ionization potentials, are not detected as efficiently as other elements. The detected mass balance is usually group III rich. An entire mass spectrum is necessary for complete characterization of all elements and adjustment of their RSF's because many sputtered molecules are detected containing the group V elements. Multiply charged species compose about 10% of the detected ions.

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“…The use of non-resonant multiphoton ionization for the detection of sputtered neutral particles has been reviewed [16]. Here some of the issues of particular significance to energy distribution measurements are discussed.…”

Section: Non-resonant Multiphoton Ionizationmentioning

confidence: 99%

“…Non-resonant multiphoton ionization of sputtered neutrals can be a highly sensitive and non-species-specific technique [14,15]. Although the general uniformity of ionization efficiency of sputtered multicomponent neutral particles is still being debated [16,17], the technique has proved to be the most efficient when compared to other methods.…”

Section: Introductionmentioning

confidence: 99%

Energy distributions of copper ions and atoms sputtered by atomic and molecular ions

Wang¹,

Nor²,

Graham

1997

J. Phys. D: Appl. Phys.

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Non-resonant multiphoton ionization combined with quadrupole and time-of-flight analysis has been used to study sputtering by both atomic and molecular ion beams. The mass spectra and energy distributions of both sputtered atoms and secondary ions produced by 3.6 keV , , , and ion bombardment at to a polycrystalline copper target have been measured. The energy distributions of the copper ions and atoms are found to be different and quite complex. The ion distributions can generally be described by a linear collision cascade model, with possible evidence for a knock-on contribution. The sputtered atom distributions are partially described by a combination of linear collision cascade and dense cascade (thermal spike) models. This is interpreted as support for a time-evolving sputtering mechanism.

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Influence of laser parameters on the detection efficiency of sputtered neutrals mass spectrometry based on non-resonant multiphoton ionization

Cited by 30 publications

References 33 publications

Surface Analysis by Laser Ionization

Surface Analysis by Laser Ionization

Characterization of InGaAsP materials by ultrahigh intensity post-ionization mass spectrometry: Relative sensitivity factors for zinc versus bulk constituents

Energy distributions of copper ions and atoms sputtered by atomic and molecular ions

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