Transmission infrared spectroscopy of high area solid surfaces. A useful method for sample preparation

Ballinger, Todd H.; Wong, Jason C. S.; Yates, John T.

doi:10.1021/la00042a031

Cited by 95 publications

(103 citation statements)

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“…36 Sample preparation involved pressing the SiO 2 nanoparticles into a tungsten grid support (Tech-Etch). 36,37 The tungsten grids were 2 × 3 cm 2 . Each grid was 50 μm thick with 100 grid lines per inch.…”

Section: Methodsmentioning

confidence: 99%

Atomic Layer Etching of HfO₂Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)₂and HF

Lee

DuMont

George

2015

ECS J. Solid State Sci. Technol.

118

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The atomic layer etching (ALEt) of HfO 2 was performed using sequential, self-limiting thermal reactions with tin(II) acetylacetonate (Sn(acac) 2 ) and HF as the reactants. The HF source was a HF-pyridine solution. The etching of HfO 2 was linear with atomic level control versus number of Sn(acac) 2 and HF reaction cycles. The HfO 2 ALEt was measured at temperatures from 150-250 • C. Quartz crystal microbalance (QCM) measurements determined that the mass change per cycle (MCPC) increased with temperature from −6.7 ng/(cm 2 cycle) at 150 • C to −11.2 ng/(cm 2 cycle) at 250 • C. These MCPC values correspond to etch rates from 0.070 Å/cycle at 150 • C to 0.117 Å/cycle at 250 • C. X-ray reflectivity analysis confirmed the linear removal of HfO 2 and measured an HfO 2 ALEt etch rate of 0.11 Å/cycle at 200 • C. Fourier transform infrared (FTIR) spectroscopy measurements also observed HfO 2 ALEt using the infrared absorbance of the Hf-O stretching vibration. FTIR analysis also revealed absorbance features consistent with HfF 4 or HfF x surface species as a reaction intermediate. The HfO 2 etching is believed to follow the reaction: HfO 2 + 4Sn(acac) 2 + 4HF → Hf(acac) 4 + 4SnF(acac) + 2H 2 O. In the proposed reaction mechanism, Sn(acac) 2 donates acac to the substrate to produce Hf(acac) 4 . HF allows SnF(acac) and H 2 O to leave as reaction products. The thermal ALEt of many other metal oxides, as well as metal nitrides, phosphides, sulfides and arsenides, should be possible by a similar mechanism. Atomic layer etching (ALEt) is a thin film removal technique based on sequential, self-limiting surface reactions.1-3 ALEt can be viewed as the reverse of atomic layer deposition (ALD). 4 ALEt is able to remove thin films with atomic layer control. ALD and ALEt are able to provide the necessary processing techniques for surface engineering at the atomic level. 5,6 This atomic level control is needed for the nanofabrication of a wide range of nanoscale devices. 7Until recently, ALEt processes have been reported using only ionenhanced or energetic noble gas atom-enhanced surface reactions. [1][2][3] In these ALEt processes, a halogen is adsorbed on the surface of the material. Subsequently, ion or noble gas atom bombardment is used to desorb halogen compounds that etch the material. Using this approach, ALEt has been reported for Si,2,3,[8][9][10][11][12] Ge, 6,13 and compound semiconductors.14-17 ALEt has also been demonstrated for a variety of metal oxides. 7,[18][19][20] Additional ALEt studies have been conducted on various carbon substrates. 21-23The ALEt of Al 2 O 3 was recently reported using sequential, selflimiting thermal reactions with Sn(acac) 2 and HF as the reactants. 24The linear removal of Al 2 O 3 was observed at temperatures from 150-250• C without the use of ion or noble gas atom bombardment. Al 2 O 3 ALEt etch rates varied with temperature from 0.14 Å/cycle at 150• C to 0.61 Å/cycle at 250• C. 24 The Sn(acac) 2 and HF thermal reactions were both self-limiting versus reactant exposure. In addition, the Al 2...

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Section: Methodsmentioning

confidence: 99%

Atomic Layer Etching of HfO₂Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)₂and HF

Lee

DuMont

George

2015

ECS J. Solid State Sci. Technol.

118

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“…The tungsten grid had dimensions of 2 cm Â 3 cm, a thickness of 0.005 cm, and a grid spacing of 39 lines/cm. Polished stainless steel dies and a manual press were used to press the SiO 2 particles into the tungsten grid [21,22].…”

Section: Methodsmentioning

confidence: 99%

SiO2 film growth at low temperatures by catalyzed atomic layer deposition in a viscous flow reactor

George

2005

Thin Solid Films

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“…All in situ FTIR spectra were obtained using an in situ FTIR cell as described by Yates and coworkers [14,15]. The cell was constructed within a standard stainless-steel tee having conflat flanges and commercial CaF 2 windows.…”

Section: In Situ Ftir Cellmentioning

confidence: 99%

Investigation of the effect of carbon monoxide on the oxidative carbonylation of methanol to dimethyl carbonate over Cu+X and Cu+ZSM-5 zeolites

Anderson

Root

2004

Journal of Molecular Catalysis A: Chemical

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Transmission infrared spectroscopy of high area solid surfaces. A useful method for sample preparation

Cited by 95 publications

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Atomic Layer Etching of HfO₂Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)₂and HF

Atomic Layer Etching of HfO₂Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)₂and HF

SiO2 film growth at low temperatures by catalyzed atomic layer deposition in a viscous flow reactor

Investigation of the effect of carbon monoxide on the oxidative carbonylation of methanol to dimethyl carbonate over Cu+X and Cu+ZSM-5 zeolites

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Transmission infrared spectroscopy of high area solid surfaces. A useful method for sample preparation

Cited by 95 publications

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Atomic Layer Etching of HfO2Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)2and HF

Atomic Layer Etching of HfO2Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)2and HF

SiO2 film growth at low temperatures by catalyzed atomic layer deposition in a viscous flow reactor

Investigation of the effect of carbon monoxide on the oxidative carbonylation of methanol to dimethyl carbonate over Cu+X and Cu+ZSM-5 zeolites

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Atomic Layer Etching of HfO₂Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)₂and HF

Atomic Layer Etching of HfO₂Using Sequential, Self-Limiting Thermal Reactions with Sn(acac)₂and HF