RF Microwave Plasma Generator

Email: sixmhz@yahoo.com

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This page details how a RF plasma source of approximately 1 kW can be constructed from house-hold materials. Possible uses include plasma cleaner, plasma etch, remote activation species generation and no use at all (my personal favorite).

How it works

This is about the simplest high-power RF plasma source you can get. The RF power source is a standard 2.4 GHz microwave oven with minimal modifications. Inside the microwave oven is a non-metallic evacuated chamber with a pressure of ~1 torr or less. As the RF power is switched on (I use power setting of HIGH, but 'popcorn' also works pretty well), a couple of stray electrons in the semi-evacuated chamber get accelerated and smash into the remaining gas molecules in the chamber. When the gas molecules get hit with an electron, they get ionized (turn into a plasma) and give off light and additional electrons which cause more ionization. This plasma is now self-sustaining at the appropriate chamber pressures.

What you need to do

First you'll need to score a microwave. Any one will do, doesn't matter if it smells or where you get it as long is it fires. Next up is the vacuum chamber. I used an empty beer bottle with a nylon hose barb epoxied into the opening. Now I think I should mention that it would be important (as always) not to use any metallic fittings or other parts inside the microwave oven-so don't. Then I stuck some rubber vacuum hose onto the hose barb attached to the chamber as means to evacuate it with the microwave on. But you are thinking, if the door is closed, where does the hose come out? Well you're gonna need to take the back panel off the microwave and drill a hole into the main cooking chamber and jam the vacuum hose through it. Also you'll need to drill a hole in the microwave cover to get the hose out the back because you WILL *IMPORTANT* put the panel back on the microwave before operation or you will get cooked with RF radiation.

Now just hook that vacuum hose up to your favorite roughing pump and turn on the pumper. Wait till the pressure gets pretty low and turn on the RF. So now you have what I call a 'no use' plasma source. Can't get the plasma out of there or nothing else in the bottle. Here's where the glass-blowers come in to make a nice chamber that you can open and close. I leave this to you...

Last updated: 05/23/04
Copyright 2004, Greg Miller