Transparent Conducting Oxides
Q. Sputtering apllications and especially TCO applications both with ceramic and metallic targets. I want to control my process better.
I have MRC 943.
I am looking for some informations about Speedflo system.
Is it possible with this kind of installations ?
A. Yes Speedflo is designed to control reactive sputtering processes. It can also be used in non-reactive processes for better long term stability.
So if you run from a metallic target with O2 then that is reactive and it will increase rates and produce more controlled films.
If you run from ceramic, with say a small amount of O2, it can monitor the level of metal and O2 in the plasma and control stoichiometry over the long term.
Ionized Cu emissions
Q. I am using Speedflo to try to detect ionized copper in a HIPIMS discharge. What emission lines should I look at (325nm)?
A: The 325 nm range wavelength is for non-ionised Cu (in spectral terms is Cu I is non-ionised copper,.. which is different from Cu(I) in chemistry,.. The 1+ ionised copper corresponds to Cu II in spectral terms,... confusing).
For ionised Cu we should see the following lines:
368.7 nm relative intensity: 1,000
491.0 nm relative intensity: 1,000
627.3 nm relative intensity: 1,000
As a reference the intensity for non-ionised Cu in the attached spectrum are (according to NIST database):
324.7 nm relative intensity: 10,000
327.4 nm relative intensity: 10,000
510.5 nm relative intensity: 1,500
515.3 nm relative intensity: 2,000
521.8 nm relative intensity: 2,500
For Ar we should see a very busy spectrum on the blue side but we could preselect some lines that would give us the info we need.
Cleaning PEM Optics
Q. I have partially coated the light focusing lens in PEM head. How should I clean this?
A. First refer to the assembly drawing in the manual.
- Remove the compression screw 03
- Remove O-ring 05
- Remove lens 06
- Remove O-ring 04
- Pull the fibre out by removing component 08 from bellow 07. BEWARE that fibre optic is attached to component 08. Avoid excessive force that could damage the optical fibre 01.
Cleaning of components:
Lens: generally gentle wipe with H2O2 ~ 10% v/v is enough. In some cases HCl ~5% is also needed to be added.
Phosphor bronze components: Use mechanical metal-polish cleaning or etching solution (e.g. 100 mL water + 15 g Oxalic acid + 30 mL H2O2 30%)
Stainless Steel components: Use mechanical metal-polish cleaning or etching solution (e.g. 100 mL water + 15 g Na4-EDTA+ 30 mL H2O2 30%)
Note: coating of the lens can be reduce or eliminated by bleading a small amount of Argon into the collimtaing tube. Also, if the Argon signal is used as a ratio to the gas or metal signal, the reduction in signal as it coats is normalised.
SiO2 process gas control
Q: We have rcently started a new project which requires the deposition of
reactive SiO2 via magnetron sputtering. Our cathode size is 6"x49". I
have a few years of experience with this type of sputtering but have
always used manual gas control to maintain the desired target voltage on
the oxygen hysteresis curve. I am interested in the closed loop type
controller to better maintain our film quality and plasma stability.
Thank You for your help
A: Yes, you can use Speedflo for that. For SiO2 we
can work off the target voltage and then adjust the MFC to hold the
process on the hysteresis curve. For that size of target we would
recommend two MFC's - split the gas distribution into 2 sections. That
will hold the target condition better and improve uniformity.
We can supply the gas bars as well if required which should make the
process easier to tune in terms of uniformity and deposition rate.
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