Laser-induced chemical etching of silicon in chlorine atmosphere

Mogyorsi, P.; Piglmayer, K.; Kullmer, R.; Buerle, D.

doi:10.1007/bf00617934

Cited by 48 publications

(5 citation statements)

References 19 publications

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“…Reported photo-assisted etching yields are much lower for Si (100) in the presence of Cl 2(g) with longer wavelength light. 10,11,65,66 For example, the yield was 3.34 Â 10 À4 Si atoms/photon at 248 nm and 6.46 Â 10 À6 Si atoms/photon at 308 nm using pulsed excimer lasers at a Cl 2 pressure of 525 mTorr. 66 The yield was 2.88 Â 10 À6 Si atoms/photon at 488 nm and 2.13 Â 10 À6 Si atoms/photon at 514.5 nm under continuous Ar þ laser irradiation in a 750 Torr Cl 2 atmosphere.…”

Section: Mechanisms For Photo-assisted Etchingmentioning

confidence: 99%

“…66 The yield was 2.88 Â 10 À6 Si atoms/photon at 488 nm and 2.13 Â 10 À6 Si atoms/photon at 514.5 nm under continuous Ar þ laser irradiation in a 750 Torr Cl 2 atmosphere. 11 Kullmer and D. B€ auerle 10 found that with low laser fluence, etching was non-thermal and ascribed the process to the reaction between photoelectrons and Cl radicals on the surface to form Cl À , which then penetrates the sub-surface region.…”

Section: Mechanisms For Photo-assisted Etchingmentioning

confidence: 99%

“…Etching of p-type Si induced by photo-generated carriers in a Cl 2 atmosphere was also obtained using a pulsed 308 nm XeCl excimer laser 10 and cw Ar þ and K þ lasers with various wavelengths. 11 Schwentner et al systematically investigated photo-induced etching of Cu [12][13][14][15] and GaAs 16 with Cl 2 , and etching of Si with XeF 2 [17][18][19] using synchrotron radiation in the vacuum UV (VUV) range. They found that photo-induced etching was strongly wavelength-dependent, with the maximum yield exhibited around 120 nm.…”

Section: Introductionmentioning

confidence: 99%

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Photo-assisted etching of silicon in chlorine- and bromine-containing plasmas

Zhu

Sridhar

Liu

et al. 2014

Journal of Applied Physics

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feed gases diluted in Ar (50%-50% by volume) were used to study etching of p-type Si(100) in a rf inductively coupled, Faraday-shielded plasma, with a focus on the photo-assisted etching component. Etching rates were measured as a function of ion energy. Etching at ion energies below the threshold for ion-assisted etching was observed in all cases, with Br 2 /Ar and HBr/Cl 2 /Ar plasmas having the lowest and highest sub-threshold etching rates, respectively. Sub-threshold etching rates scaled with the product of surface halogen coverage (measured by X-ray photoelectron spectroscopy) and Ar emission intensity (7504 Å). Etching rates measured under MgF 2 , quartz, and opaque windows showed that sub-threshold etching is due to photon-stimulated processes on the surface, with vacuum ultraviolet photons being much more effective than longer wavelengths. Scanning electron and atomic force microscopy revealed that photo-etched surfaces were very rough, quite likely due to the inability of the photo-assisted process to remove contaminants from the surface. Photo-assisted etching in Cl 2 /Ar plasmas resulted in the formation of 4-sided pyramidal features with bases that formed an angle of 45 with respect to h110i cleavage planes, suggesting that photo-assisted etching can be sensitive to crystal orientation. V

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Section: Mechanisms For Photo-assisted Etchingmentioning

confidence: 99%

Section: Mechanisms For Photo-assisted Etchingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photo-assisted etching of silicon in chlorine- and bromine-containing plasmas

Zhu

Sridhar

Liu

et al. 2014

Journal of Applied Physics

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“…Numerical calculations on the basis of the underlying reaction-diffusion equation reveal a broad distribution of these species with long tails over length scales > 100 mm. [18][19][20] Most notably, variations of the bromine atom concentration in the focal area are negligible (cf. shaded rectangle in Figure 3).…”

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confidence: 99%

Photothermally Induced Microchemical Functionalization of Organic Monolayers

et al. 2009

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“…Laser-stimulated silicon etching has been frequently studied as a dry etching in gaseous media (1)(2)(3). However, the photoetching of n-Si can be examined also in water solutions of electrolytes, but in this case lasers with high power densities [e.g., 107 W cm 2 (4)] are needed.…”

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confidence: 99%

Laser Etching of n‐Si

Švorčı́k

Rybka

1991

J. Electrochem. Soc.

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The etching of n-Si in water solution of fluorine salts initiated by HeNe and HeCd laser light was studied as a function of laser power density. It was calculated that for exposure to low power density, the temperature of the sample remains unchanged and the only decisive factor is the density of incident photons. The recombination of photogenerate electronhole pairs was shown to be negligible: The principle of the laser-initiated etching of n-Si in the water solutions of selected fluorine salts is described.Laser-stimulated silicon etching has been frequently studied as a dry etching in gaseous media (1-3). However, the photoetching of n-Si can be examined also in water solutions of electrolytes, but in this case lasers with high power densities [e.g., 107 W cm 2 (4)] are needed. In Ref. (5), the samples in the solutions of fluorine salts were exposed to the light of VIS lasers with low power density. It was shown in this case that the etching rate is affected by polymeric structure of the salts, the wave length of the incident light, and by the power density of the lasers in use. Photoelectric principle of the etching process was supposed. The anodic photodissolution of silicon in fluoridecontaining media has been investigated, the etch rate depends upon the applied potential (6).The aim of this work was to study the silicon etching in salt solutions, initiated by CW laser radiation. The effects of the laser power density and the radiation wavelength were examined. ExperimentalThe photoetching of(100) mSi:P (n = 3 -101~ atom-cm -3) was stimulated by HeNe laser (k = 633 nm, power density Pd = 10 W cm ~) or by HeCd laser (k = 441nm, Pd = 40 W cm -2) in experimental setup described earlier in (7, 8). The laser power density was changed by means of absorbing filters. Water solution of NH4HF2 with concentrations of 2.5 and 5.0 tool. 1 ~ was used as an etchant and the etched depths were measured by means of a profilometer.1.97 eV for HeCd and HeNe lasers. So that, at different power densities mentioned above, both lasers deliver approximately the same number of photons to the sample surface initiating the etching process.Generally, the rate of the semiconductor etching initiated by the laser light which can be viewed as a surface reaction, is closely related to the photogeneration of the electron-hole pairs, their recombination, and diffusion to the sample surface or out of the reaction region. The later process may be neglected in the present case. The reason is that for 100 ~m laser spot, no significant underetching takes place. The electron-hole creation is necessary condition of photoetching. This fact was confirmed in the separate experiment in which the etchant solution was exposed to the laser beam parallel to the sample surface and no etching was observed in spite of the fact that the salt was initiated. The similar results were reported in Ref.(2). The etching rate depends on the surface density of the electron-hole pairs, which in turn is closely related to the energy density of the incident light, absorpti...

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Laser-induced chemical etching of silicon in chlorine atmosphere

Cited by 48 publications

References 19 publications

Photo-assisted etching of silicon in chlorine- and bromine-containing plasmas

Photo-assisted etching of silicon in chlorine- and bromine-containing plasmas

Photothermally Induced Microchemical Functionalization of Organic Monolayers

Laser Etching of n‐Si

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