Computational Methods

 

 

Density Functional Theory (DFT)

 

Trend of miniaturized size in semiconductor devices made ALD become the most promising method to deposit conformal and high quality silicon based thin films. To study the reaction mechanism in ALD process, theoretical study method has gained many interest due to the low cost with precise results.

 

In our group, we extensively studied the effect of the silicon precursors on the ALD reaction by DFT calculation using Dmol3 package from Material Studio 7.0.

 

DFT studies capable to calculate:

• Bond dissociation energy in molecules (example: BDE of ALD precursors)

• Adsorption energy of precursors into the surface

• Energy of reaction (thermodynamically and kinetically)

 

1. L. L. Yusup, J.-M. Park, Y.-H. Noh, S.-J. Kim, W.-J. Lee, S. Park, and Y.-K. Kwon, “Reactivity of different surface sites with silicon chlorides during atomic layer deposition of silicon nitride,” RSC Adv., vol. 6, no. 72, pp. 68515–68524, 2016.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Finite Element Method (FEM)

 

Stress and/or thermal distribution in a device may or may not be uniform, this matter could cause a structural failure lead to mechanism failure of the device [1]. Information of thermal/stress distribution gain from theoretical study would be useful for optimizing device design parameters as the actual experiments of the parameters could be costly and time-consumming. These parameters can be studied by FEM, where the problems solved by dividing problem's domain into small elements [2].

 

In our study, the stress behavior in materials studied by finite element method (FEM) using ANSYS simulation software.

 

1. S. H. Seo, J. S. Hwang, J. M. Yang, W. J. Hwang, J. Y. Song, and W. J. Lee, “Failure mechanism of copper through-silicon vias under biased thermal stress,” Thin Solid Films, vol. 546, pp. 14–17, 2013.

2. http://en.wikipedia.org/wiki/Finite_element_method