Sticking probabilities of H2O and Al(CH3)3 during atomic layer deposition of Al2O3 extracted from their impact on film conformality

Abstract

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Initial Growth Study of Atomic-Layer Deposition of Al2O3 by Vibrational Sum-Frequency Generation

“…Furthermore, the surface chemistry has also been studied quantitatively looking at the reactivity (initial sticking probability or reaction cross section), reaction kinetics (activation energy), and reaction thermodynamics (potential energy change). 35,36,38−42 However, for most ALD processes the growth mechanism is known at a qualitative level at best.…”

Conformality of atomic layer deposition in microchannels: impact of process parameters on the simulated thickness profile

“…as (free) molecular flow, Knudsen flow, or Knudsen diffusion. 4,19,25,26 Diffusion-reaction models based on Fick's law of diffusion can flexibly be used in free molecular flow (Kn >> 1) as well as in transition flow (Kn  1) and even in ‡ Diffusion-reaction models relying on Fick's laws of diffusion are in the ALD literature sometimes somewhat confusingly referred to as "continuum" models; 4,30,33 in this work the term is dedicated to continuum flow conditions where the mean free path of molecules  (m) is orders of magnitude smaller than the limiting feature dimension h (m) (Knudsen number Kn = /h  10 -3 ). 25 continuum flow (Kn << 1) conditions, 24,26,27 as the effective diffusion coefficient Deff (m -2 s -1 ) can be calculated from the gas-phase diffusion coefficient DA (m -2 s -1 ) and the Knudsen diffusion coefficient DKn (m -2 s -1 ).…”

“…4,7,13,17,20,29 Experimental knowledge of sticking coefficients has been rather scarce until recently. 4,7,8,11,12,[29][30][31] The most straightforward way of analysing the kinetics is by interpreting film termination profiles measured in dedicated test structures or in a cross-flow reactor, where a steep film termination profile is generally associated with high reactivity. 11,12,29,30,32,33 Recently, microscopic lateral high-aspect-ratio (LHAR) test channels have emerged for thickness profile measurements.…”

“…4,7,8,11,12,[29][30][31] The most straightforward way of analysing the kinetics is by interpreting film termination profiles measured in dedicated test structures or in a cross-flow reactor, where a steep film termination profile is generally associated with high reactivity. 11,12,29,30,32,33 Recently, microscopic lateral high-aspect-ratio (LHAR) test channels have emerged for thickness profile measurements. 18,[34][35][36] Such LHAR structures simplify conformality analysis: after ALD, the roof of the structure can be removed, exposing the film to detailed analysis.…”

Evidence for low-energy ions influencing plasma-assisted atomic layer deposition of SiO2: Impact on the growth per cycle and wet etch rate

“…A schematic cross-sectional side view of the used LHAR structures (PillarHall ™ generation 3 and 4, developed by Puurunen and co-workers) 18,19,[23][24][25][26][27][28][29] is provided in Figure 1A, also illustrating film growth during plasma exposure. Using a network of Si pillars, a polysilicon membrane is suspended above a Si substrate with a nominal gap height of 500 nm to form a high-aspect-ratio horizontal trench.…”