Problem epi2 SNF 2008-09-18 11:47:43: Thickness Variation is over 10%

[slcheng at snf.stanford.edu]

I measured the Ge film on Si from Wollam.
The Thickness vs differnet position is shown below:
Positoin (cm)    x-direction(um)  y-direction(um)
-3	1.0078	0.9296
-2	0.9945	0.9417
-1	0.9807	0.953
0	0.9666	0.9666
1	0.9546	0.9825
2	0.9443	0.9972
3	0.9345	1.0131
I only measure 6cm range from the center.
It's already about 10% variation. 
Is it becasue the susceptor is not sitting flat enough and cause a temperature gradient?