I apologize if this seems ignorant, but I am at a loss and I need some assistance. I recently built a small vacuum PVD system (Ion source, argon, target material, substrate cradle, etc.) and was showing it to a colleague when it was noticed that my system was unbiased. It actually didn't occur to me to bias the system when I was building it, but my substrate cradle is made from an insulator so it is definitely unbiased. My question is, how is it that it works?? Because it definitely works; I get a good coating on every substrate I sputter. Any help?