Fundamentals of Chemical Vapor Deposition: Notation Used in the Tutorial






Gases, Kinetic Theory



symbol

standard units

description

alternative units

P

Pa

Pressure

Torr, atm

V

m3

volume

cm3, liter

N

moles

number of moles

R

J/mole K

universal gas constant

liter atm/mole °C, torr liter/mole °C

T

K

temperature

°C

m

kg

molecular mass

gm, amu

k

joules/K

Boltzmann's constant

ev/K, erg/K

v

m/s

molecular velocity

cm/s

c

m/s

average molecular velocity (various)

cm/s

J

#/m2 sec

flux (number crossing unit area/time)

#/cm2 sec

n

#/m3

molecular density

#/cm3

M

g/mole

molar mass

kgm/mole

λ

m

mean free path

cm

a

m

effective molecular diameter

cm



Reactor Analysis



X

[dimensionless]

utilization

Rs

moles/second

surface reaction rate

molecules/second

Ks

m/sec

surface reaction rate constant (first order)

cm/second

S

m2

surface area

cm2

[species]

moles/m3

concentration of species

moles/cm3, molecules/cm3

Q

moles

total reactant

molecules

Fin

m3/sec

volumetric flow in (or out)

cm3/sec

tres

seconds

residence time

tcon

seconds

consumption time

NAv

#/gm mole

Avogadro's number




Mass Transport




D

m2/sec

diffusion constant

cm2/sec

A

m2

cross-sectional area

cm2

Ld

m

diffusion length

cm

L

m

characteristic system length

cm

Pe

[dimensionless]

Peclet number = (feature size/diffusion length)^2

ρm

moles/m3

molar density

moles/cm3

ρ

kg/m3

mass density

g/cm3

U

m/sec

fluid velocity

cm/sec

μ

kg/m sec

viscosity

gm/cm sec = Poise

Re

[dimensionless]

Reynolds number = (feature size/momentum diffusion length)^2

Fsccm

std. cm3/min

molar flow (standard units)

H

m

height of chamber

cm

r

m

radial distance

cm

Rc

m

radius of chamber

cm

Fm

moles/second

molar flow

C

molecules/m3

molar concentration

moles/cm3

LTh

m

Thiele length

cm

ν

m2/sec

kinematic viscosity, μ/ρ

cm2/sec



Heat Transport




cp

J/kgm

heat capacity at constant pressure

J/gm

cvol

J/m3

volumetric heat capacity

J/cm3

Kth

W/m K

thermal conductivity

W/cm K

c

m/s

velocity of light

cm/s

Sigma

W/m2 K4

Stefan-Boltzmann constant

W/cm2 K4

ϵ

[dimensionless]

emissivity

Pm

W/m2

radiated power

W/cm2

d

m

gap between planes

cm





Chemistry




G

Joules/mole

free enthalpy or Gibbs Free Energy

calories/mole

S

Joules/mole K

entropy

calories/mole

E

Joules/mole

internal energy

calories/mole

H

Joules/mole

enthalpy

calories/mole

ΔHvap

Joules/mole

heat of vaporization

calories/mole

Ea

Joules/mole

activation energy

calories/mole

θ

[dimensionless]

fraction of occupied surface sites

RSC

[dimensionless]

reactive sticking coefficient




Return to Tutorial Table of Contents
Book version of the CVD Tutorial