Bonding States and Coverage Calculations for HfO2 Deposited on H2O Terminated Si (100)-2x1 Using Atomic Layer Deposition

Abstract

A one-cycle ALD growth reaction on the water terminated Si(100)-2x1 surface is shown to lead to successful nucleation, high metal oxide coverage, and an abrupt metal-oxide/silicon interface as confirmed by XPS, RHEED, and RBS measurements. Photoemission results confirm the coordination states of the hafnium and oxygen atoms. A Hf 4f core level shift is observed and assigned to the presence of the Si-O-Hf bonding environment with the more electronegative Si atom inducing the binding energy shift. This Hf 4f shift is smaller than that reported previously for silicates because of the difference of the semiconductor bonding environment. Experiments indicate that the hydroxyl sites bound to Si(100) are active for ligand exchange reactions. The abrupt interface could be useful for aggressive Effective Oxide Thickness (EOT) scaling.