Evelyn,
       Barium Strontium Titanate is an oxide. When you sputter it you
are going to be producing Barium, Strontium, Titanium and Oxygen atoms.
It is unlikely that they are going to reform a stoichometric film on the
target if RF sputtered. The oxygen is likely to go down the high vacuum
turbo pump/cryo system.

RF and DC sputtering is used for metals and simple compounds. Though
there is sputtered Quartz, it is fairly slow and if I remember correctly
it was full of stress. Oxides are also not conductive and that might
have complications. You couldn't do DC sputtering at all.

RF and DC sputtering has to be done in a high vacuum with argon.

I am not an expert on PLD, but I assume you can do it with a fairly good
background pressure of oxygen, perhaps a few millitorr, which would make
sure that your film would be stoichometric and not a suboxide.

For film formation, one size doesn't fit all. Also, you can't always get
everything that you want even even though you might have every possible
deposition method you want.

Edward H. Sebesta
Principal Engineer Advanced Electronics Packaging (No longer
"Independent")



-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Evelyn B
Sent: Friday, March 06, 2009 5:03 PM
To: General MEMS discussion; Evelyn Benabe
Subject: [mems-talk] PLD Vs RF Sputtering Deposition of BST Films


Hi,

I have been doing a little bit of literature research about deposition
of BST-5 films on MgO substrates and have found that most the films are
deposited using Pulsed Laser Deposition (PLD) systems instead of RF
Sputtering.  I was under the understanding that RF sputtering was
superior than PLD because it provides smoother surfaces, better
uniformity, higher breakdown voltage, and lower losses.  Why is PLD then
chosen as the deposition method for MgO substrates?

Evelyn