Advanced Process Control of HfxSi1-xO2 Composition using Co-injection Atomic Layer Deposition

A novel Atomic Layer Deposition (ALD) process has been developed in which chemical precursors are co-injected and simultaneously reacted. The process demonstrates hafnium silicate films of uniform composition that can be easily tuned from <30 to >80 % Hf concentration to meet specific device requirements with excellent thickness control proportional to the number of process cycles. The film has been fully integrated into a CMOS structure and provides repeatable parametric results over a wide range of film compositions. In addition we review a VUV metrology technique correlated to X-ray photoelectron spectroscopy that enables measurement of the hafnium vs. silicon composition in very thin films <50 Aå, with sensitivity to lower hafnium concentration in the interfacial layer for films deposited directly upon silicon substrates.