Application of thin crystalline Si3N4 liners in shallow trench isolation (STI) structures

摘要

Silicon integrated circuits use a crystalline layer of silicon nitride (Si3N4) in shallow trench isolation (STI) structures as an O2-barrier film. The crystalline Si3N4 lowers the density of electron traps as compared with as-deposited, amorphous Si3N4. Further, a larger range of low-pressure chemical-vapor deposited (LPCVD) Si3N4 films can be deposited, providing a larger processing window for thickness controllability. An LPCVD-Si3N4 film is deposited at temperatures of 720°C to 780°C. The deposited film is in an amorphous state. Subsequently, a high-temperatures rapid-thermal anneal in pure nitrogen or ammonia is conducted at 1050°C to 1100°C for 60 seconds.