Abstract
The conformality of thin films grown by atomic layer deposition (ALD) is studied using all-silicon test structures with long narrow lateral channels. A diffusion model, developed in this work, is used for studying the propagation of ALD growth in narrow channels. The diffusion model takes into account the gas transportation at low pressures, the dynamic Langmuir adsorption model for the film growth and the effect of channel narrowing due to film growth. The film growth is calculated by solving the diffusion equation with surface reactions. An efficient analytic approximate solution of the diffusion equation is developed for fitting the model to the measured thickness profile. The fitting gives the equilibrium constant of adsorption and the sticking coefficient. This model and Gordon's plug flow model are compared. The simulations predict the experimental measurement results quite well for Al2O3 and TiO2 ALD processes.
Original language | English |
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Article number | 205301 |
Journal | Journal of Applied Physics |
Volume | 123 |
Issue number | 20 |
DOIs | |
Publication status | Published - 28 May 2018 |
MoE publication type | A1 Journal article-refereed |
Funding
This work received funding from the Academy of Finland through the Finnish Centre of Excellence in Atomic Layer Deposition and from Tekes (since 2018 Business Finland) through the PillarHall TUTL Project. The samples were fabricated at the Micronova Clean Room Facilities of VTT, Espoo.