Glow Discharging Carbon Films with the Emitech K350 Attachment

1. Mount a few carbon-coated grids to a clean glass slide by sticking the grids to the edge of a piece of double-sticky tape attached to the slide (Fig. 1).
2. Put on latex or nitrile gloves. Do not touch anything in the chamber with your bare hands.
3. Make sure that one end of the five-pin plug is plugged into the back of the K350 (glow discharge unit - not into the back of the K950X main unit) and the other end into the back end of the K150X film thickness monitor (FTM) (Fig. 2).
4. Turn on the power of all three units. The switch is above the power plugs in the back of the units on the right side on the K950X and the glow discharge unit and in the back on the left of the FTM.
5. Tip back the carbon evaporation unit that is on top of the bell jar of the K950X. Place your grids on the stage inside the chamber. If you have your grids taped to a microscope slide there is a slide-shaped recess for it on the stage (Fig. 3).
6. Place the glow discharge head on top of the chamber and check to see that it is firmly seated (Fig. 4).
7. Hit the START button on the K950X. The turbo molecular pump speed will begin to increase. The vacuum, as observed on the LCD of the K950X, should start to improve almost immediately. If it doesn't, hit the STOP button and clean the rubber seal on the top of the bell jar and on the contact area of the head with your finger.
8. When the turbo pump speed reaches 100% the vacuum should read approximately 2X10^-1 mbar. Adjust the needle valve slightly if it doesn't.
9. Check to make sure that the TIMER dial on the K350 is set beyond the time you will need for glow discharging and the DEPOSITION dial is set to zero. (Fig. 5).
10. Make sure that the polarity button on the glow discharge unit is set to negative (NEG) and then hit Start (Certain applications may require a POS setting). The LED next to the START button will light.
11. Slowly increase the DEPOSITION current on the glow discharge unit until the needle on the dial registers ~20 mA. You should see a purple glow inside the K950X chamber below the target.
12. Maintain the glow for a minimum of 30 seconds to 1 minute. Depending on your application, a time of up to 2 minutes may be required. Your grids are properly hydrophilic when a drop of water immediately spreads out over the entire surface of the grid when applied.
13. Hit the STOP button on the glow discharge unit, turn the DEPOSITION current down to zero, and then hit the STOP button on the main K950X unit. Air will be pulsed into the chamber. When the unit comes to atmosphere you may remove your grids. Do not close the needle valve when you are done, leave it where it is.
14. Place the glow discharge head back on top of the K350 control unit and cover it with the protective plastic bag. Lower the carbon coating unit back onto the bell jar. It is not necessary to re-evacuate the chamber.
15. Turn off the power on all of the units. Your grids should be used as soon as possible, preferably no longer than 30 minutes.

Fig. 1. Carbon coated grids attached to slide with double-sticky tape.


Fig. 2. Back of the glow discharge (top) and FTM (bottom) units.


Fig. 3. Inside the evaporation chamber. The recess where the slide sits and the FTM crystal are marked.


Fig. 4. Glow discharge head.

Fig. 5. Front panel of the K350 glow discharge unit.