We are depositing Cu, Zn and Sn by co sputtering (DC biased magnetron) at room temperature on SLG (substrate temp). We find our film has poor adhesion with SLG. What is the best method to improve its adhesion? I have some thoughts in my mind like:

1) giving bipolar biasing to substrate

2) heating substrate to some temperature(say 150 or 200) during deposition

Are these solutions effective?

If not which are the possible ways?