For Silicon, we need stack layer (Ti/TiN) to avoid diffusion of Al inside silicon. But do we need adhesion layer for LN substrate? I tried Al electrode patterning with wet etching method, without any adhesion layer, and adhesion looks quite good in some of the devices. In few devices, some issues are there. Probably that is an issue because of dust. Still, I just want to make sure. Could someone please help me with this?