Electronic spectra of ruthenium and osmium tetroxides

Foster, S.; Felps, S.; Johnson, Lawrence W.; Larson, D.B.; McGlynn, S. P.

doi:10.1021/ja00801a010

Cited by 29 publications

(26 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The emission lines z E-mail: denis.shamiryan@imec.be have a weak correlation with electronically excited and ionized RuO 4 states either calculated theoretically 6 or observed experimentally. 7 The theoretical peak is predicted at 385 nm ͑which corresponds to the electronically allowed transition to the 1T 2 state ͕1t 1 ͓2p͑O͔͒ → 2e͑M-O͖͒, while a broad peak was experimentally observed in the limits of 350-430 nm. However, the exact peak positions do not match.…”

Section: Resultsmentioning

confidence: 93%

Highly Sensitive Monitoring of Ru Etching Using Optical Emission

Shamiryan

Baklanov

Boullart

2005

Electrochem. Solid-State Lett.

View full text Add to dashboard Cite

During Ru etch with oxygen-based plasma, strong emission lines have been observed in the region of 340-390 nm with the most prominent peak at 373 nm. These are attributed to the emission of neutral Ru. We have shown that the emission can be used for end-point detection for Ru patterning by plasma etch as well as for highly sensitive in situ monitoring of the etch chamber cleaning after Ru processing.Continuous scaling of metal-oxide-semiconductor field effect transistors ͑MOSFETs͒ brings challenges that cannot be resolved using conventional materials. A straightforward example is the polysilicon gate that starts showing a number of limitations as the gate size goes below 100 nm. The main limitations are high gate resistance and gate depletion. Gate depletion, which arises due to insufficient dopant activation close to the poly-Si/gate dielectric interface, lowers the surface-effective field that degrades device performance. Both problems can be overcome by using metals as the gate electrode. Metals have low resistivity and high electron density that is not subjected to depletion.Ruthenium is one of the promising candidates for the metal gate electrode. It has the appropriate work function of p-MOS devices and is thermally stable in contact with dielectrics like SiO 2 or ZrO 2 . 1 Since Ru forms volatile ruthenium tetraoxide RuO 4 ͑boiling temperature Ϸ104°C͒, it is reported to be relatively easily patterned by ozone gas 2 or oxygen plasma. 3 It was found that addition of 10% Cl 2 increases the etch rate. This might be due to the fact that chlorine can increase the concentration of oxygen radicals and ions. 4 No etch products other than RuO 4 and some RuO 3 ͑such as RuF 5 ͒ were observed during etching of RuO 2 with O 2 /CF 4 plasma. Exposure of RuO 2 to Cl 2 plasma left some Cl on the surface ͑as found by X-ray photoelectron spectroscopy, XPS͒ but no Ru chloride. 4 Attempts to etch RuO 2 with SF 6 /Ar, BCl 3 /Cl 2 , SF 6 /BCl 3 /Ar were reported to be unsuccessful; no ruthenium-containing species were detected in the downstream emission by Fourier transform ion cyclotron resonance ͑FTICR͒ spectroscopy. 5 It can be concluded that no plasma other than an O 2 -containing is known to etch Ru ͑or RuO 2 ͒. The optical emission was studied during the etching of ruthenium oxide by oxygen-containing plasma. It was shown that the emission can be used for end-point detection, and it was assumed that a possible source of the emission is Ru atoms. 5 Knowledge of the emission spectra is necessary to develop etch monitoring during patterning of Ru metal gates. On the other hand, the optical emission spectroscopy of electronically excited radicals is extremely sensitive and can be used for quantitative monitoring of small amounts of Ru contaminating the etch chamber.In this paper we present experimental data on optical emission spectra, characteristic for the Ru etch process and demonstrate their utility for the end-point detection during Ru patterning and for Ru contamination monitoring in the etch chamber after processing of R...

show abstract

Section: Resultsmentioning

confidence: 93%

Highly Sensitive Monitoring of Ru Etching Using Optical Emission

Shamiryan

Baklanov

Boullart

2005

Electrochem. Solid-State Lett.

View full text Add to dashboard Cite

show abstract

“…This important feature of electronic spectra is typical of many tetraoxo ions and all known neutral tetroxide ions and molecules: MnO − 4 , CrO 2− 4 [30], OsO 4 and RuO 4 [29], and FeO 4 [34,35]. For the mentioned ions, progressions on the totally symmetric mode ( 1 ) are observed in the spectra of single crystals.…”

Section: Vibrational Structure Of the Spectrummentioning

confidence: 88%

“…OsO 4 and MnO 4 − [29,30]) are also related to the bands of charge-transfer of [ (O)→M] type. A more detailed interpretation of PuO 4 spectrum will be possible only after the relevant quantumchemical computation is realized.…”

Section: Interpretation Of the Electronic Spectrummentioning

confidence: 99%

On existence and properties of plutonium(VIII) derivatives

et al. 2014

View full text Add to dashboard Cite

The existence of Pu(VIII) was shown in alkaline solutions and in nonpolar solvents (CCl 4 and CHCl 3 ) on the ground of such experimental facts like extraction of plutonium species, obtained by means of ozonization of Pu(VI) alkaline solutions into CCl 4 and CHCl 3 ; volatility of Pu compounds out of aqueous alkaline solutions, and the mentioned solvents. The product of interaction between PuO 3 ⋅ 0.8H 2 O and XeF 2 in CCl 4 and CHCl 3 was of the same chemical form for both cases and identical with the form of the product of volatility of Pu out of these organic solutions. The electronic absorbance spectra of these products in CCl 4 and CHCl 3 were fairly similar to the ones for OsO 4 and RuO 4 . The band of absorption in these spectra with the maximum at 332 nm corresponds to the charge transfer of metal-ligand type [ (O)→Pu], as the value of molar extinction coefficient was found to be higher than 2 × 10 3 L/mole cm. A satisfactory agreement between the energies for the transitions of PuO 4 molecule designed by X -SW method and experimental data was observed. A similar accordance was observed for the designed vibration frequency (DFT-method) with the one found as result of analysis of the vibration structure of the experimental spectra.Keywords: Plutonium, Tetraoxide of plutonium, Electron absorption spectra of tetraoxide of plutonium, Volatility of tetraoxide of plutonium, Quantum chemical simulation of the structure of tetraoxide of plutonium.

show abstract

“…The tetrahedral molecule Ru04 absorbs at 26000 cm-' ( 'A, -+'T2) in the gas phase [23,24] and should in the liquid or solid state be a very suitable candidate for a one-photon experiment: the Ru04 entities essentially retain their electronic integrity in the crystal and intermolecular interactions are weak [25]. There is very little conventional absorption at 52000 cm-' [23,24] and this wavenumber corresponds to the 192.3 nm wavelength available from the powerful argon fluoride exciplex lasers.…”

Section: Suggested Experimentsmentioning

confidence: 99%

“…There is very little conventional absorption at 52000 cm-' [23,24] and this wavenumber corresponds to the 192.3 nm wavelength available from the powerful argon fluoride exciplex lasers. However, the compound exhibits a complex photochemistry [ 261.…”

Section: Suggested Experimentsmentioning

confidence: 99%

Selection rules for bimolecular photoabsorption

Andrews

Bittner

1992

Chemical Physics

View full text Add to dashboard Cite

Bimolecular photoabsorption1s a term descnbing processes m which two molecules or other chemically dtstmct entities undergo srmultaneous excitatron to electronic excited states, the energy bemg provided by the absorption of one or more laser photons. These processes have previously been referred to as synergistic, cooperative, or mean-frequency absorption. Thts paper introduces a new terminology for the description of such phenomena and provides an overvtew of the features associated wtth bimolecular processes mvolving the absorption of one, two or three photons from a smgle laser beam. Emphasis is placed on a detailed symmetry analysis based on irreducible tensors, leading to a comprehenstve treatment of the selection rules for all the maJor molecular point groups. Finally, attention is drawn to some systems in which these effects have been detected, and others m which they m&t be expected to occur.

show abstract

Electronic spectra of ruthenium and osmium tetroxides

Cited by 29 publications

References 1 publication

Highly Sensitive Monitoring of Ru Etching Using Optical Emission

Highly Sensitive Monitoring of Ru Etching Using Optical Emission

On existence and properties of plutonium(VIII) derivatives

Selection rules for bimolecular photoabsorption

Contact Info

Product

Resources

About