Dry Oxygen Tetraethyl Ortho Silicate Anneal
Original Publication Date: 1985-May-01
Included in the Prior Art Database: 2005-Feb-18
A novel anneal process, as illustrated in the figure, using dry oxygen and gaseous hydrogen chloride has been developed which does not result in excessive oxidation of collector contacts in high performance, advanced bipolar transistor processing. The thickness of oxide resulting from this method can be easily removed by the standard P-contact wet etch. In high performance advanced bipolar transistor processing Tetraethyl Ortho Silicate (TEOS) can be used as a source for low pressure chemical vapor deposition (LPCVD) for "underlay and overcoat" oxides. The TEOS LPCVD deposition is normally followed by an anneal in steam at about 800ŒC. During this anneal the heavily doped collector contact oxidizes, forming about 1500-2000 ˜ thick additional silicon dioxide relative to the transistor base and Schottky barrier diode contacts.