The growth rate in ALD (Atomic Layer Deposition) is usually saturated to a constant thickness when sufficient source and reactant are injected. In ALD process, very good time set of growth rate (thickness/time) is not found at saturation time set region but found at unsaturation time set region. To find good time set of growth rate, many experiments are needed because of many combinations of time set. As a result, prediction of time set of growth rate by the Model is necessary in unsaturation time regiont.
The growth rate is affected by sticking probability, size, injection pulse time, partial pressure of adsorption molecule and process temperature. If the temperature and partial pressure are fixed in process condition, the growth rate is only limited by sticking probability, size, injection pulse.
The Model is developed for the calculation of the growth rate from sticking probability parameters on the surface and size of adsorption molecules. They are extracted from saturation data of source and reactant. Then adsorption coverages (α, β, γ, δ) are defined and their values are used to obtain a value of layer/cycle in Model.
To prove this Model, TiN ALD is experimented with TDMAT(Tetra dimethyl-amino titanium) and $NH_3$. As a result, the growth rate of TiN saturated to 1.25 layer/cycle when source and reactant injection time is sufficient. And then a few experimental data to predict values of calculation by the Model are obtained in unsaturation time set region.
The results of calculation by the Model are compared with experimental values of TiN ALD. Model predicts for time set combinations very well. Also, TDMAT is adsorptive on $NH_3$ surface more than on TiN surface and $NH_3$ is on TiN surface more than on TDMAT surface from extracted sticking probability parameter.
