In situ atomic layer nitridation on the top and down regions of the amorphous and crystalline high-K gate dielectrics

摘要

Amorphous and crystalline ZrO2 gate dielectrics treated with in situ atomic layer nitridation on the top and down regions (top and down nitridation, abbreviated as TN and DN) were investigated. In a comparison between the as-deposited amorphous DN and TN samples, the DN sample has a lower leakage current density (J(g)) of similar to 7 x 10(-4) A/cm(2) with a similar capacitance equivalent thickness (CET) of similar to 1.53 nm, attributed to the formation of SiOxNy, in the interfacial layer (IL). The post-metallization annealing (PMA) leads to the transformation of ZrO2 from the amorphous to the crystalline tetragonal/cubic phase, resulting in an increment of the dielectric constant. The PMA-treated TN sample exhibits a lower CET of 1.22 nm along with a similarig of 1.4 x 10(-5) A/cm(2) as compared with the PMA-treated DN sample, which can be ascribed to the suppression of IL regrowth. The result reveals that the nitrogen engineering in the top and down regions has a significant impact on the electrical characteristics of amorphous and crystalline ZrO2 gate dielectrics, and the nitrogen incorporation at the top of crystalline ZrO2 is an effective approach to scale the CET and J(g), as well as to improve the reliability. (C) 2016 Elsevier B.V. All rights reserved.