Problem AG4108 SNF 2009-10-09 05:59:04: Thin oxides for QUAL1150 ....

[shott at snf.stanford.edu]

Preliminary measurements of the oxide thickness of the QUAL1150 look significantly thinner than they should.  Also, based on imput from Peter Griffin, they appear to fall in a range where it is very difficult to accurately determine the thickness and index.
When I use the program that determines both thickness and refractive index I get:
Wafer	Thickness	Refractive Index
1	62.5	1.999
6	65.1	2.084
11	63.7	2.096
16	62.1	2.046
21	64.8	2.025
When I assume the index is 1.46 I get:
Wafer	Thickness
1	75.5
6	78.8
11	76.5
16	74.8
21	78.2
Peter Griffin notes that these measurement both have the same Psi and Del:
 index	 thick	psi	del
1.46	75 	10.88 	157.98
2.00	65 	10.79 	156.85
While I will confirm that we DO have an oxide layer by etching in 50:1 HF, I think that we may have some sort of temperature and/or pyrometer calibration problem.
Thanks,
John