Why do you need sputter rate standards anyway? Each ion source will produce a different sputter rate depending on the conditions that the ion source is operated at, as well as other factors such as the angle of the ion source to the sample. Changing the beam voltage, condenser and focus (beam size), pressure (amount of argon or other gas) and raster area all affect the sputter rate. By using a sputter rate standard you can characterize your ion source for a particular set of operating conditions for a known oxide layer thickness of standard material (Ta2O5 or SiO2).
To further complicate things, the sputter rate of different materials varies greatly and that makes it very difficult to accurately know the true sputter rate for compounds and multi layer samples.
The link to this SPECs article for some very helpful insights into sputter rates on different materials:
Sputter Rate Information
And, here is a link to a PNNL publication on the sputter rates of oxide films relative to SiO2.
TaO5 sputter rate standard
RBD Instruments provides a 1000 Angstrom oxide layer TaO5 sputter rate standard which is approximately .75 X .50 inch in size. Both sides of the standard can be used, so one standard can last a long time. The RBD part number is TA2O5RE.
SiO2 sputter rate standard
RBD Instruments provides a 1000 Angstrom oxide layer SiO2 sputter rate standard which is approximately .50 X .50 inch in size and comes in a two pack. The RBD part number is SIO2CALRE and like the TaO5 standard, both sides can be used.
To request a quote for either standard, contact RBD here or go to the upper right hand corner of the RBD Instruments website and create a sales ticket. (www.rbdinstruments.com)