Hello,

I am trying to deposit a-C layers via DC Magnetron (balanced) sputtering on steel. However, the film starts to delaminate via buckling right after i expose the chamber to the atmosphere. The film seems to be stable for as long as a vacuum is kept. So i am thinking that it might not be a problem of intrinsic stress.

I usually evacute the chamber up to 3x10^-5 mbar. Ar pressure is around 1.5*10^-2.

Deposition happens around 500V with a current of ~0.3A for 300s. (which is working ok on Si Wafers)

I tried doing sputter cleaning with a DC Bias before deposition, which seems to help but definetly doesnt stop the buckling. (300V for 15min at 8*10^-2)

I can only use Ti as an Interlayer but not in same chamber, so i have to expose the substrate after interlayer deposition to the atmosphere...When it tried it, buckling seemed to get worse...

Also DC Bias of 60 V or 75 V didnt help, but made it worse since buckling already happened under vacuum (i gues due to higher intrinsic stress).

Anyone know other reasons for buckling, especially after exposure to atmosphere?

Many thanks in advance for any input!