Chemical Vapor Deposition (CVD)

Question 1

How can the uniformity of concentration of the reactant gas and deposition along the wafer be improved?

Answer 1

By mixing the reactant gas in an inert gas.

Question 2

What is a heterogeneous CVD process?

Answer 2

A process that favors the formation of solids at a surface.

Question 3

What is a homogeneous CVD process?

Answer 3

Formation of reaction products in the gas (not at the surface).

Question 4

What is the law of mass action?

Answer 4

K_p(T) = p_Bp_C²/p_A

A ⇔B + 2C

p_i = partial pressure of substance i

K_p(T) = reaction equilibrium constant

Question 5

What is a kinetically controlled process?

Answer 5

A process that is not in equilibrium (typically low pressure).

Question 6

Hva er plasma?

Answer 6

Ionisert gass, med lignende ledningsevne som metall.

Question 7

Hva står forkortelsene for?

LPCVD

PECVD

HDPCVD

APCVD

Answer 7

LPCVD = Low Pressure CVD

PECVD = Plasma Enhanced CVD

HDPCVD = High Density Plasma CVD

APCVD = Atmospheric Pressure CVD

Question 8

Hvilken gass brukes oftest til epitaxy av Si?

Answer 8

Klorsilan (chlorosilane)

SiH_xCl_4-x

x = 0,1,2,3