Mean free path of particles in gaseous medium¶

The atoms of the target material evaporate and move towards the substrate inside the magnetron. At the same time, it collides with gas atoms. The free path length is the distance that a traveling atom travels between two collisions.

Notation:

\(k_\text{B}\) (k_B) is boltzmann_constant.

Notes:

Assuming the model of spherical gas molecules, \(\sigma = pi d^2\), where \(\sigma\) is the cross section and \(d\) is the molecule diameter.

Links:

mean_free_path¶: mean_free_path of particle.

Symbol:: lambda
Latex:: \(\lambda\)
Dimension:: length

pressure¶: pressure of the gas.

Symbol:: p
Latex:: \(p\)
Dimension:: pressure

temperature¶: temperature of the gas.

Symbol:: T
Latex:: \(T\)
Dimension:: temperature

cross_section¶: cross_section of the interaction between the particle and the gas.

Symbol:: sigma
Latex:: \(\sigma\)
Dimension:: area

law¶

lambda = k_B * T / (sqrt(2) * p * sigma)

Latex:: \[\lambda = \frac{k_\text{B} T}{\sqrt{2} p \sigma}\]