Angle resolved X-ray photoelectron spectroscopic study of ultrathin oxynitrides

Kawase, Kazumasa; Tanimura, Junji; Kurokawa, Hiroshi; Kobayashi, Kenzo; Teramoto, Akinobu; Ogata, Tomohiko; Inoue, Masashi

doi:10.1016/s1369-8001(99)00019-0

Cited by 16 publications

(19 citation statements)

References 21 publications

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“…19) The N 2 þ radical that reaches the film/ substrate interface forms Si 3 N configuration at this interface because the silicon substrate is nitrided readily much better than the SiO 2 film. 19,21) In the case of using Xe/N 2 plasma, the concentration of the nitrogen atoms forming N high configuration is very small because the generation efficiency of N 2 þ radical is very low. interface are reduced because the N 2 þ radicals that reach the film/substrate interface are few [see Fig.…”

Section: Resultsmentioning

confidence: 99%

Control of Nitrogen Depth Profile near Silicon Oxynitride/Si(100) Interface Formed by Radical Nitridation

Kawase

Suwa

Higuchi

et al. 2006

jjap

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Depth profiles of composition and chemical structures in radical nitrided silicon oxynitride films formed with Ar/N 2 , Xe/N 2 , or Ar/NH 3 plasma excited by microwave have been investigated by X-ray photoelectron spectroscopy combined with step etching in HF solution. The relationship between the intensities of emission from N 2 þ radical in these plasmas and the concentration of nitrogen atoms forming Si 3 N configuration near the silicon oxynitride film/Si substrate interface nitrided using these plasmas was studied. The emission intensities from N 2 þ radical generated in Xe/N 2 or Ar/NH 3 plasma are a quarter or one-sixth of that from N 2 þ radical generated in Ar/N 2 plasma respectively. However, the emission from NH radical is also detected in Ar/NH 3 plasma. Although the nitrogen concentration of Xe/N 2 plasma is smaller than that of Ar/N 2 plasma at the film/substrate interface, that of Ar/NH 3 plasma is larger than that of Ar/N 2 plasma at the interface. It is important for the reduction of the nitrogen concentration near the film/substrate interface to use Xe/N 2 plasma in which both of the generation efficiencies of N 2 þ and NH radicals are low.

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Section: Resultsmentioning

confidence: 99%

Control of Nitrogen Depth Profile near Silicon Oxynitride/Si(100) Interface Formed by Radical Nitridation

Kawase

Suwa

Higuchi

et al. 2006

jjap

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“…The silicon oxide film grown by dry O 2 is estimated to be 2.2 nm thick by the method of using peak intensity ratio of silicon oxide (Si 4ϩ ) and silicon substrate (Si 0ϩ ) on the Si 2p core-level XPS spectrum assuming uniformly silicon oxide formation. [20][21][22][23] It is clarified that the SiC is not decomposed by 2.2 nm dry O 2 oxidation. Figure 3b shows the C 1s core-level XPS spectrum of the silicon We investigated the temperature dependence of hydrogen desorption and SiC formation to clarify the mechanism of the SiC formation.…”

Section: Resultsmentioning

confidence: 99%

XPS Study of H-Terminated Silicon Surface under Inert Gas and UHV Annealing

Kawase¹,

Tanimura²,

Kurokawa³

et al. 2005

J. Electrochem. Soc.

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We have investigated the changes of chemical bonding states of an H-terminated silicon surface under inert gas (Ar,N 2 ) and ultrahigh vacuum ͑UHV͒ annealing using X-ray photoelectron spectroscopy ͑XPS͒ and thermal desorption spectroscopy ͑TDS͒. SiC is formed ͑corresponding to ϳ0.1 monolayer͒ under inert gas and UHV annealing at around 500°C, which is coincident with the temperature of the dangling bonds formation at the silicon surface by hydrogen desorption, whereas SiC is not formed under O 2 annealing. From the precise analysis using a combination of XPS and TDS, the SiC formation is related to the reaction between the silicon surface and the organic contamination that is unavoidably adsorbed during air exposure. We also studied the electrical properties of metal oxide semiconductor capacitors with a chemical vapor deposited silicon oxide gate insulator formed on Ar-and O 2 -annealed silicon surfaces. Ar preannealing increases the leakage current by approximately 10 Ϫ4 times compared with O 2 annealing.It is of great importance to obtain high reliability in less than 1.5 nm thick silicon oxide gate dielectrics for 65 nm metal oxide semiconductor ͑MOS͒ devices. Pyrogenic oxides have been frequently applied for the gate dielectrics up to the present. In a conventional furnace, an uncontrollable oxide layer is grown at low temperatures in the preannealing process because O 2 gas in the air unavoidably enters the furnace chamber simultaneously at the wafer loading step. 1 The growth of the uncontrollable oxide layer deteriorates the reliability of the gate dielectrics because the time-dependent dielectric breakdown ͑TDDB͒ characteristic of a MOS capacitor with silicon oxide film grown by dry O 2 at low temperature is inferior to that with a pyrogenic oxide film grown at high temperature. 1 A furnace equipped with a load lock chamber that can control residual O 2 is necessary to prevent the uncontrollable oxide layer formation. H-termination with HF treatment is also necessary to remove the chemical oxide layer formed by the RCA cleaning process and to deactivate the silicon surface. 2-7 Although the uncontrollable oxide or the chemical oxide layer is only about 1 nm thick, it is necessary to prevent the formation of these oxide layers to realize 1.5 nm thick, highly reliable gate dielectrics. Previously, it was reported that the TDDB characteristic for MOS capacitors degrades when using a load lock chamber after HF treatment. 8 It would be caused by remaining organic contamination or etching on the silicon surface by residual O 2 and H 2 O. 9,10 However, a microscopic mechanism for the TDDB degradation still remains unclear.In this paper, we investigate the influence of inert gas (Ar,N 2 ) and ultrahigh vacuum ͑UHV͒ annealing with a load lock chamber on the chemical bonding state and roughness of H-terminated silicon surfaces by X-ray photoelectron spectroscopy ͑XPS͒ and thermal desorption spectroscopy ͑TDS͒ analysis and atomic force microscopic ͑AFM͒ observation. The insulation characteristics of gate dielectric...

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“…The thicknesses of the SiO 2 films were estimated from the intensity ratio of the Si 2p core-level photoelectron peak arising from the SiO 2 film (Si 2p 4þ ) to the same peak arising from the Si substrate (Si 2p 0þ ). [11][12][13] The XPS measurement was performed on the SiO 2 films whose thicknesses were changed by step etching with 0.3% HF solution. HF etching rates were evaluated from the etching time dependence of the SiO 2 film thicknesses left after the HF step etching.…”

Section: Methodsmentioning

confidence: 99%