I am trying to use TMAH to under-etch single crystalline Si to form released amorphous Si structures. The width of the under-etch is approximately 10 um. However, as far as I know, TMAH also attacks some metals like Al. Since I want the metal remains on my samples after the wet etching process to make electrical contacts, do you know what types of metals (namely gold, nickel, etc...) I can use?

Thank you.