Fabrication of High-k/Si Structure Using Metal Deposition Followed by Oxidation

Abstract

Hf-metal deposition followed by oxidation directly on Si substrate was presented for the fabrication of HfO2/Si gate stacks. During all of the HfO2/Si fabrication process, such as Hf-metal sputtering deposition and its ECR plasma oxidation, the substrate temperature was maintained at room temperature. HfO2 films fabricated using this process on Si substrates show lower leakage current level with a large k-value (~24). XPS measurements show no sub-oxide layer except Si2+ signal in the HfO2/Si structure. It suggests the HfO2/Si gate stack have an ideal abrupt interface with the presence of only Hf-O-Si bonds on atomically flat Si(100) plane, neither IL-SiO2 nor hafnium-silicide layer.