Thermal Desorption Behavior of AlF3Formed on Al2O3

Watanabe, Morimichi; Iida, Takashi; Akiyama, Keijiro; Ishikawa, Takahiro; Sakai, Hiroaki; Sawabe, Kyoichi; Shobatake, Kosuke

doi:10.1143/jjap.42.l680

Cited by 3 publications

(3 citation statements)

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“…At the higher temperatures, enhanced interface and surface roughness is induced (TEM, AFM), possibly by etch reactions by F at the surface, a by-product of the WF 6 chemisorption reaction. 28 The higher temperature could induce more nucleation events, with crystal growth in more random directions as a result of the higher surface roughness. Scharf et al described a similar temperature dependent orientation of the WS 2 crystals for the WS 2 ALD from WF 6 /H 2 S in combination with diethylzinc.…”

mentioning

confidence: 99%

Low temperature deposition of 2D WS₂ layers from WF₆ and H₂S precursors: impact of reducing agents

et al. 2015

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confidence: 99%

Low temperature deposition of 2D WS₂ layers from WF₆ and H₂S precursors: impact of reducing agents

et al. 2015

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“…͑5͒, as tabulated in Table III. 33 F atoms were detected as the desorbed species at sample temperatures of T s = 625-850 K and their intensities were found to peak at T s = 750 K. AlF 2 species were identified as desorbed species above T s = 850 K. We have concluded that AlF 3 is reduced to subfluoride, AlF x ͑x = 1 and/or 2͒, and AlF 2 is the species desorbed from the reduced AlF x ͑x = 1 and/or 2͒ layer via a sublimation process. Although not shown in Table III, the vapor pressures of the AlF 3 dimer, i.e., Al 2 F 6 , are about two orders of magnitude smaller than those of the monomer.…”

Section: A Desorption Behavior Of Alf 3 Speciesmentioning

confidence: 99%

“…The vapor pressures of AlF 3 have been presented over the temperature range from 1238°C͑1 Torr͒ to 1537°C͑760 Torr͒ 18,19 and are thus believed to be very low at temperatures below 900 K. If the vapor pressure of AlF 3 were very low, AlF 3 would not be desorbed from the surface. 16 Thus, thermodynamics of the vapor pressure of AlF 3 is discussed. There is some discrepancy among the vapor pressures listed by Stull 18 and the NIST Standard Reference Database 19 and our results.…”

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Thermal reaction of polycrystalline AlN with XeF2

Watanabe

Mori

Ishikawa

et al. 2005

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Articles you may be interested inComprehensive surface analysis of GaN-capped AlGaN/GaN high electron mobility transistors: Influence of growth method J. Appl. Phys. 110, 083527 (2011); 10.1063/1.3653825 AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor with low temperature liquid phase deposited Al 2 O 3 gate insulator Low coverage spontaneous etching and hyperthermal desorption of aluminum chlorides from Cl 2 / Al (111) J. Chem. Phys. 121, 9018 (2004); 10.1063/1.1805495 Selected energy epitaxial deposition of GaN and AlN on SiC(0001) using seeded supersonic free jets of NH 3 in helium J.Detailed studies on the thermal reaction behavior of polycrystalline aluminum nitride ͑AlN͒ with effusive xenon difluoride ͑XeF 2 ͒ have been carried out over the sample temperature ͑T s ͒ range from 300 to 920 K using molecular beam mass spectrometry combined with a time-of-flight technique and ex situ surface analyses, i.e., X-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron microscopy ͑SEM͒. The species desorbed from the AlN / XeF 2 system were monitored using molecular beam mass spectrometry, as a function of sample temperature. Above T s = 800 K, the desorbed reaction products were identified as N 2 and AlF 3 , and their flux intensities increase monotonically as the sample temperature is increased. The flux intensity of XeF 2 desorbed after physisorption to the AlN surface is found to decrease as T s is raised above T s = 800 K, and approximately one half of the incoming XeF 2 is consumed by the thermal reaction at 920 K. The results of surface analyses show that the thermal reaction of AlN with XeF 2 starts at approximately T s = 700 K, forming a reaction layer composed of AlF 3 . The AlF 3 layer becomes thick as T s is increased from T s = 700-800 K. Above T s = 800 K, however, as a result of fast desorption of AlF 3 and F atoms from the AlF 3 layer, only partially fluorinated AlF x ͑x = 1 and/or 2͒ layers are formed and the bulk AlN is revealed again. The SEM photographs indicate that the surfaces exposed above T s = 850 K are strongly etched but a slight change is observed at T s ഛ 800 K. On the basis of these results, three reaction stages are proposed for the AlN / XeF 2 reaction depending on the sample temperature range: Stage 1 ͑300ഛ T s Ͻ 700 K͒; no reaction, stage 2 ͑700ഛ T s Ͻ 800 K͒; surface fluorination, and stage 3 ͑800ഛ T s ͒; etching. At stage 3, AlF 3 formed on the surface starts to evaporate and fast etching proceeds, since the vapor pressure of AlF 3 is high enough in this temperature range.

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Desorption and sublimation kinetics for fluorinated aluminum nitride surfaces

King

Davis

Nemanich

2014

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The adsorption and desorption of halogen and other gaseous species from surfaces is a key fundamental process for both wet chemical and dry plasma etch and clean processes utilized in nanoelectronic fabrication processes. Therefore, to increase the fundamental understanding of these processes with regard to aluminum nitride (AlN) surfaces, temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) have been utilized to investigate the desorption kinetics of water (H2O), fluorine (F2), hydrogen (H2), hydrogen fluoride (HF), and other related species from aluminum nitride thin film surfaces treated with an aqueous solution of buffered hydrogen fluoride (BHF) diluted in methanol (CH3OH). Pre-TPD XPS measurements of the CH3OH:BHF treated AlN surfaces showed the presence of a variety of Al-F, N-F, Al-O, Al-OH, C-H, and C-O surfaces species in addition to Al-N bonding from the AlN thin film. The primary species observed desorbing from these same surfaces during TPD measurements included H2, H2O, HF, F2, and CH3OH with some evidence for nitrogen (N2) and ammonia (NH3) desorption as well. For H2O, two desorption peaks with second order kinetics were observed at 195 and 460 °C with activation energies (Ed) of 51 ± 3 and 87 ± 5 kJ/mol, respectively. Desorption of HF similarly exhibited second order kinetics with a peak temperature of 475 °C and Ed of 110 ± 5 kJ/mol. The TPD spectra for F2 exhibited two peaks at 485 and 585 °C with second order kinetics and Ed of 62 ± 3 and 270 ± 10 kJ/mol, respectively. These values are in excellent agreement with previous Ed measurements for desorption of H2O from SiO2 and AlFx from AlN surfaces, respectively. The F2 desorption is therefore attributed to fragmentation of AlFx species in the mass spectrometer ionizer. H2 desorption exhibited an additional high temperature peak at 910 °C with Ed = 370 ± 10 kJ/mol that is consistent with both the dehydrogenation of surface AlOH species and H2 assisted sublimation of AlN. Similarly, N2 exhibited a similar higher temperature desorption peak with Ed = 535 ± 40 kJ/mol that is consistent with the activation energy for direct sublimation of AlN.

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Thermal Desorption Behavior of AlF₃Formed on Al₂O₃

Cited by 3 publications

References 8 publications

Low temperature deposition of 2D WS₂ layers from WF₆ and H₂S precursors: impact of reducing agents

Low temperature deposition of 2D WS₂ layers from WF₆ and H₂S precursors: impact of reducing agents

Thermal reaction of polycrystalline AlN with XeF2

Desorption and sublimation kinetics for fluorinated aluminum nitride surfaces

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Thermal Desorption Behavior of AlF3Formed on Al2O3

Cited by 3 publications

References 8 publications

Low temperature deposition of 2D WS2 layers from WF6 and H2S precursors: impact of reducing agents

Low temperature deposition of 2D WS2 layers from WF6 and H2S precursors: impact of reducing agents

Thermal reaction of polycrystalline AlN with XeF2

Desorption and sublimation kinetics for fluorinated aluminum nitride surfaces

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Product

Resources

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Thermal Desorption Behavior of AlF₃Formed on Al₂O₃

Low temperature deposition of 2D WS₂ layers from WF₆ and H₂S precursors: impact of reducing agents

Low temperature deposition of 2D WS₂ layers from WF₆ and H₂S precursors: impact of reducing agents