Review of Kinetic Theory
Molecules in an ideal gas have a Maxwellian velocity distribution:
with mean velocity:
Note in this formula you must use R in joules/kgm-mole!
The number of molecules impinging on a plane per square centimeter each second:
Leading to a very important result: the maximum possible deposition flux for a given partial pressure of precursor, the
Knudsen Equation:
[where for convenience here P is in Torr, M in grams/mole, and J in molecules/cm2 second]
The mean free path of each molecule is:
Notation:
N = number of moles (or molecules)
v = absolute value of velocity vector v
m = molecular mass
k = Boltzmann's constant, 1.38x10-23 J/K
R = universal gas constant
M = molar mass
n = molar volume N/V
a = effective molecular diameter
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