Analysis of the uncertainty in the measurement of electron densities in plasmas using the wave cutoff method

Kim, Jung-Hyung; Kwon, Jeong Hyun; You, S. J.; Seong, Dong-Ook; Shin, Young-Han

doi:10.1088/0026-1394/42/2/005

Cited by 22 publications

(12 citation statements)

References 20 publications

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“…The uncertainty by the broadening of cutoff peak, including the error by frequency resolution, is considered to be about 20%. 13 In spite of these matters, electron density measurement by FCP showed remarkable results. Therefore, we can conclude that the Fourier cutoff probe method can measure the electron density without a network analyzer, with reliability and a very high-time resolution.…”

Section: Resultsmentioning

confidence: 99%

“…13 The frequency of cutoff peak and the electron density was also known to be well matched. [13][14][15] Since the cutoff probe was developed, a lot of remodeled versions of the cutoff probe have been developed, including phase-resolved method, 16 hybrid-type of cutoff probe with absorption probe, 17,18 and cutoff probe with box-car mode for pulsed plasma measurement. 19 Normally, the cutoff probe consists of two coaxial cables with their cores exposed to and immersed in the plasma.…”

Section: Introductionmentioning

confidence: 89%

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Cutoff probe using Fourier analysis for electron density measurement

You

Kim

et al. 2012

Review of Scientific Instruments

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This paper proposes a new method for cutoff probe using a nanosecond impulse generator and an oscilloscope, instead of a network analyzer. The nanosecond impulse generator supplies a radiating signal of broadband frequency spectrum simultaneously without frequency sweeping, while frequency sweeping method is used by a network analyzer in a previous method. The transmission spectrum (S21) was obtained through a Fourier analysis of the transmitted impulse signal detected by the oscilloscope and was used to measure the electron density. The results showed that the transmission frequency spectrum and the electron density obtained with a new method are very close to those obtained with a previous method using a network analyzer. And also, only 15 ns long signal was necessary for spectrum reconstruction. These results were also compared to the Langmuir probe's measurements with satisfactory results. This method is expected to provide not only fast measurement of absolute electron density, but also function in other diagnostic situations where a network analyzer would be used (a hairpin probe and an impedance probe) by replacing the network analyzer with a nanosecond impulse generator and an oscilloscope.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

Cutoff probe using Fourier analysis for electron density measurement

You

Kim

et al. 2012

Review of Scientific Instruments

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“…The relation between the cutoff frequency and electron density is given by n e = ω pe 2 ϵ 0 m e / e 2 , where ϵ 0 is the vacuum permittivity, e is the elementary charge, and m e is the electron mass. The cutoff method provides high accuracy (uncertainty under 2%) , in the measurement of absolute electron density due to its simple equation without any specific assumptions.…”

Section: Methodsmentioning

confidence: 99%

Role of Oxygen in Amorphous Carbon Hard Mask Plasma Etching

Yeom,

Yoon,

Choi

et al. 2023

ACS Omega

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In the current and next-generation Si-based semiconductor manufacturing processes, amorphous carbon layer (ACL) hard masks are garnering considerable attention for highaspect-ratio (HAR) etching due to their outstanding physical properties. However, a current limitation is the lack of research on the etching characteristics of ACL hard masks under plasma etching conditions. Given the significant impact of hard mask etching on device quality and performance, a deeper understanding of the etching characteristics of ACL is necessary. This study aims to investigate the role of oxygen in the etching characteristics of an ACL hard mask in a complex gas mixture plasma etching process. Our results show that a small change of oxygen concentration (3.5−6.5%) can significantly alter the etch rate and profile of the ACL hard mask. Through our comprehensive plasma diagnostics and wafer-processing results, we have also proven a detailed mechanism for the role of the oxygen gas. This research provides a solution for achieving an outstanding etch profile in ACL hard masks with sub-micron scale and emphasizes the importance of controlling the oxygen concentration to optimize the plasma conditions for the desired etching characteristics.

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“…5 shows a linear increase in the measured plasma density generated in an oxygen background as a function of total electron beam current. 36,37 The error bars are determined using the methods described in 38 for Langmuir probes and 39 for wave-cutoff probes. Fig.…”

Section: Plasma Productionmentioning

confidence: 99%

Electron Beam Generated Plasmas for Ultra Low T_eProcessing

Walton

Boris

Hernández

et al. 2015

ECS J. Solid State Sci. Technol.

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The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc.), ionization is driven by a high-energy (∼ few keV) electron beam, an approach that can be attractive to atomic layer processing applications. In particular, high electron densities (10 10 -10 11 cm −3 ) can be produced in electron beam generated plasmas, where the electron temperature remains between 0.3 and 1.0 eV. Accordingly, a large flux of ions can be delivered to substrate surfaces with kinetic energies in the range of 1 to 5 eV. This provides the potential for controllably etching and/or engineering both the surface morphology and chemistry with monolayer precision. This work describes the electron beam driven plasma processing system, with particular attention paid to system characteristics and the ability to control the generation and delivery of ions to the surface and their energies. Electron beam generated plasmas are produced by injecting a highenergy electron beam into a gas background, which will ionize, dissociate, and excite atoms or molecules as it traverses the gas volume. While the basic inelastic processes that lead to species production are the same as those in discharge plasmas, the use of energetic electron beams to drive production results in plasmas that have very different properties than conventional discharges. Some of these properties are attractive for plasma-based atomic layer processing applications where, whether etching, depositing, or chemically modifying materials, fine control over the flux and energy of ions is needed. In the case of atomic layer etching, perhaps the single most important need is to tightly control the kinetic energy of ions incident to the processing surface so as to avoid damage while maintaining a reasonable etch rate. [1][2][3] In this regard, a significant advantage of beam-driven plasmas is the inherently low electron temperature T e , which is typically a fraction of an eV in most gas mixtures of technological interest. Importantly, this is true regardless of the plasma density. Thus, one can produce a large fluence of reactive ion and neutral species where the kinetic energy of the ions is as low as a few eV.The interest in electron beam generated plasmas for materials processing can be traced back at least 4 decades. In the early 1970s Bunshah 4 described an electron beam vapor deposition system that utilizes an electron beam to both vaporize the metal and "activate" the background gas. It was also noted by Dugdale 5 that high-energy electron beam systems developed for welding could be employed for "soft vacuum vapor deposition" in a manner similar to that of Bunshah. In the 1980s, Collins and co-workers at Colorado State University, developed electron beam produced plasmas for plasma enhanced chemical vapor deposition of SiO 2 . 6,7 This system used a sheet-like beam of multi-keV electrons injected parallel to the growth substrate. A similar configurat...

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Analysis of the uncertainty in the measurement of electron densities in plasmas using the wave cutoff method

Cited by 22 publications

References 20 publications

Cutoff probe using Fourier analysis for electron density measurement

Cutoff probe using Fourier analysis for electron density measurement

Role of Oxygen in Amorphous Carbon Hard Mask Plasma Etching

Electron Beam Generated Plasmas for Ultra Low T_eProcessing

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Analysis of the uncertainty in the measurement of electron densities in plasmas using the wave cutoff method

Cited by 22 publications

References 20 publications

Cutoff probe using Fourier analysis for electron density measurement

Cutoff probe using Fourier analysis for electron density measurement

Role of Oxygen in Amorphous Carbon Hard Mask Plasma Etching

Electron Beam Generated Plasmas for Ultra Low TeProcessing

Contact Info

Product

Resources

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Electron Beam Generated Plasmas for Ultra Low T_eProcessing