What protocol should I use to get a good stable 100nm Au adhesion onto a Si substrate using electron beam evaporation? I've heard talk of primer layers of either Cr or Ti at around 5nm thickness, as the typical way to do it. Which material should I choose? What the advantages or disadvantages of both Cr and Ti (or some other material)? They're both commonly discussed and I don't know which one to pick. (I have both available for loading sources in the lab.) When other metals such as Al is used, onto Si, it will work well with no additional adhesion layer right? What about if Ge is used as the substrate? I know the native oxide is significantly different on Ge, it's less stable and can be soluble, compared to native SiO2. I've heard that Ge itself adheres to things well and can be used as an adhesion layer. If Ge was used as the underlying substrate (same Au deposition) could the same Cr or Ti protocol still be used (same as Si), to have confidence in reliable adhesion of the metal?