The refractive index of LPCVD Silicon Dioxide should be close to 1.46.
However the ellipsometry software should be able to give you both
thickness and refractive index through a transformation on the measured
del and psi values for a single layer film.  The del and psi values are
periodic functions of the film thickness for transparent films and the
measurements are subject to error when the thickness is close to an
integer multiple of that period.  If that's the case you can get away
from the period by changing the angle of incidence.

Roger Shile

-----Original Message-----
From: mems-talk-bounces+rshile=nanoink.net@memsnet.org
[mailto:mems-talk-bounces+rshile=nanoink.net@memsnet.org] On Behalf Of
Qing Yao
Sent: Friday, May 14, 2004 9:46 AM
To: MEMS-talk
Subject: [mems-talk] refraction index of LPCVD silicon dioxide

Hi,


I was wondering if some one could tell me the typical value of
refraction
index of LPCVD Silicon Dioxide. It is deposited at about 420 degrees
centigrade on a silicon wafer. I use a focus ellipsometer to measure its
thickness. I tried 1.46 but got very large fit error (about 500). Please
let
me know if you have any information about this. Thanks!


Best Regards,


Qing Yao
___________________
M&IE @ UIUC


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