Described examples include integrated circuits, drain extended transistors and fabrication methods in which a silicide block material or other protection layer is formed on a field oxide structure above a drift region to protect the field oxide structure from damage during deglaze processing. Further described examples include a shallow trench isolation (STI) structure that laterally surrounds an active region of a semiconductor substrate, where the STI structure is laterally spaced from the oxide structure, and is formed under gate contacts of the transistor.