Making My First Successful Film

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.

Re: Making My First Successful Film

Postby Dennis P Brown » Tue Apr 18, 2017 11:42 am

The plate is biased; at those voltages and pressures the gas conducts and the ionized atoms "knock" off metal atoms that then move to and adhere to the glass. Your picture shows a rather badly "burned" film. It might just be the photo but if not, the issue of contamination looks to be a problem in your system. I don't bias my substrates but do use a DC voltage in the high hundreds (400 - 850 volts.) I've used higher voltage systems with magnetrons.

Also, your pressure is a bit on the low end. By the way, do you use air or argon? Air with oxygen can causes issues with your films.

Using an RCA cleaning process is over-kill for most sputtering systems (that is generally used only for semi-conductor systems and require ultra clean glassware ...); in any sputtering system the ionized gas will clean the substrate as long as you have first used alcohol to clean it of any minor contamination. For grossly contaminated glass surfaces using detergent and water, and then following this up by alcohol is ok.

I sputter films all the time and routinely make ultra-high quality films and I don't even bother to clean the substrates since standard slides are more than clean enough (you are using gloves to handle them?)
User avatar
Dennis P Brown
 
Posts: 1116
Joined: Sun May 20, 2012 2:46 pm
Location: Glen Arm, MD
Real name: Dennis P Brown

Re: Making My First Successful Film

Postby ian_krase » Wed Apr 19, 2017 4:04 am

I'm using air, as I don't have access to argon yet. DC voltage you mean is just the magnetron sputtering voltage? Mine is probably something similar, I don't have any instrumentation. The power supply is a rectified OBIT.

I know the pressure is a bit low. One frustrating problem is that either higher pressures or the low pressures I mentioned work due to Paschen's Law, but intermediate pressures cause the plasma to leave the magnetron. But its my impression that sputtering works at a wide range of pressures and lowering the pressure makes it more radiant.

It is 110% the light in that last picture. My workspace is poorly lit and the surroundings are not of uniform color. Most of my films are pretty much white silver.

The last film i did, with the cross, is burned/contaminated and actually is the way that picture looks.
ian_krase
 
Posts: 225
Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

Re: Making My First Successful Film

Postby Dennis P Brown » Wed Apr 19, 2017 12:10 pm

Yes, all my sputtering is done with DC.

Any good sputtered film will be a highly specular - that is, perfect mirror reflector on a piece of glass.

I sputter onto very thin plastic films (as thin as 20 microns) all the time with no trouble since sputtering and the plasma offer no significant heat load; that is not always the case for the grounding plate, however; and that can cause issues. So for thin plastic films I mount them above the ground plate using a plastic support.

Argon is popular for home based Tig welding and inexpensive (comparatively) gas systems are available in many locations. Argon is vastly superior for sputtering and allows for very high quality films to be deposited.

Scientific American has an excellent article on Sputtering in its Amateur Scientist back in the Oct 1967 issue.
User avatar
Dennis P Brown
 
Posts: 1116
Joined: Sun May 20, 2012 2:46 pm
Location: Glen Arm, MD
Real name: Dennis P Brown

Re: Making My First Successful Film

Postby Rich Feldman » Thu Apr 20, 2017 12:50 am

Dennis sure is fast!
I was about to ask who else remembered that old Amateur Scientist column, from the era that I grew up with. Really cool projects, including plenty that could kill you if followed carelessly. And things that today would scare people for miles. Amateur glassblowers could work their way up to DIY mercury-vapor diffusion pumps. Bookstores were allowed to sell the magazine to just anybody!

Ian, do you live in the San Francisco Bay area?
My day job is across the street from a company called Meivac, where they manufacture industrial sputtering systems & similar vacuum gear. I got a tour & some free stuff once, years ago, when I was mentoring some science fair kids and first joined this forum. Could find my old contact info if you're interested.
Richard Feldman
User avatar
Rich Feldman
 
Posts: 861
Joined: Mon Dec 21, 2009 11:59 pm
Location: Santa Clara County, CA, USA
Real name: Rich Feldman

Re: Making My First Successful Film

Postby ian_krase » Thu Apr 20, 2017 3:00 am

Oh, cool!

I live in the south bay area bordering on Silicon Valley, and work at a company that makes MEMS devices (though I am not at all involved in microfabrication processes). I'd love to have that info.

I've been scheming to set up argon, but it costs money and I've not yet decided to spend it especially as the results on silver are so good without it.

My sputtered films are quite specular, though the exact specularity isn't totally uniform -- there's a very faint haze in the center. Of course, it's easy to sputter long enough that spalling starts and then it's not so nice.
ian_krase
 
Posts: 225
Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

I Finally Justify My Presence On The Fusor Forums

Postby ian_krase » Tue May 16, 2017 6:32 am

I finally built a... very sloppy... demo fusor, thereby justifying my presence on the Fusor Forums, which are not really the Sputtering Forums. (I also dismounted my sputtering magnetron from my chamber)

It successfully forms a globule of plasma inside the grid, and also forms an impinging beam that must not be allowed to heat and crack/spall my glass.

Unfortunately I also managed to heat my grid (of the extremely easy and very sloppy spiral type) to incandescence and may have evaporated a small amount of copper oxide over the inside of the jar. Or maybe it's just the light.

Pictures are a series taken over the course of pumpdown. Power, as before, is provided by an oil burner ignition transformer with microwave oven diode rectifiers. This supply is capable of providing positive and negative outputs simultaneously but is capped at about 5kv, current-limited.

(unfortunately, I still don't really have the trick to properly photographing glow discharges.)
Attachments
IMG_20170515_230045.jpg
IMG_20170515_230042.jpg
IMG_20170515_230040.jpg
IMG_20170515_230012.jpg
IMG_20170515_225942.jpg
ian_krase
 
Posts: 225
Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

Re: Making My First Successful Film

Postby Richard Hull » Tue May 16, 2017 5:08 pm

Regarding heating the grid to incandescence........Don't do that.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.
User avatar
Richard Hull
Site Admin
 
Posts: 10322
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: Making My First Successful Film

Postby ian_krase » Wed May 17, 2017 1:49 am

Because of melting/evaporation, or for some other reason?
ian_krase
 
Posts: 225
Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

Re: Making My First Successful Film

Postby Dennis P Brown » Wed May 17, 2017 10:52 am

As you are noticing, metal is evaporating from your filament! That occurs when one over heats their cathode. This also tends to allow current to run along the walls reducing power to the cathode when metal is covering all the insulating surfaces in the system. A more serious issue (especially for home made systems) is that the support rod/conductor will heat up and this can weaken the feed thru sealant resulting sudden vacuum failure.

Your pictures are fine.

Glad you made your first demo fusor and got a plasma with it.
User avatar
Dennis P Brown
 
Posts: 1116
Joined: Sun May 20, 2012 2:46 pm
Location: Glen Arm, MD
Real name: Dennis P Brown

Re: Making My First Successful Film

Postby ian_krase » Wed May 17, 2017 10:41 pm

Yeah. I kinda want to try one of the tiny simple mass specs that people have posted here.

Feedthrough is probably a good point. My feedthroughs are sealed with epoxy and viton. So they don't want to get hot. Though I think they heatsink fairly well.

I'll need to clean the thing. Fortunately I have done this before (and it's nowhere near the level of total silver coatings I got when sputtering).
ian_krase
 
Posts: 225
Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

PreviousNext

Return to Images du Jour

Who is online

Users browsing this forum: No registered users and 1 guest

cron