Hi,

I have an issue with depositing TiN with a PEALD. I am using TDAMT as precursor and N2/H2 as reactive gasses in the chamber. Ar is used as purge gas and also as a bubbler gas in the precursor bottle. I use 300° C, 45° C on the bubbler, 90 to 120 °C in the line that deliver the precursor.

The recipe from the manufacturer uses 20 SCCM of H2 and N2

200 SCCM of Ar during the 0.8s of dose

3 seconds of plasma and 15 mTorr in the chamber during the plasma step.

Purging is before and after the plasma step.

The issue is that at some point the process started to not to work. The TiN layer changes color with the number of cycles. From a slightly golden color, it shifts to brown, purple and blue.

I have tried to change the recipe following some papers I found, but the result didn't change so much. Some recipes takes longer to show this color shift, but still happen.

Can be that the residues of the TDMAT, after the plasma step, are not properly pumped out and are re absorbed ?

Normally, after a certain amount of cycles, the chamber gets conductive and the plasma does not ignite anymore, since I have this problem with the deposition, I can run many more cycles, in fact, the layer deposited is not a good conductor.

Has anyone of you ever had such a problem ?