Laminated CeO{sub}2/HfO{sub}2 High-k Gate Dielectrics Grown by Pulsed Laser Deposition in Reducing Ambient

摘要

CeO{sub}2 and HfO{sub}2 dielectric layers were deposited in an Ar+(5%)H{sub}2 gas mixture by Pulsed Laser Deposition (PLD) on Si(100). A CeO{sub}2-Ce{sub}2O{sub}3 transformation is achieved by deposition in a reducing ambient. It is also shown that in-situ post deposition anneal efficiently oxidizes Ce{sub}2O{sub}3 layers to CeO{sub}2. The properties of CeO{sub}2/HfO{sub}2 laminated structures deposited in reducing ambient and compared with binary oxide layers of CeO{sub}2 and HfO{sub}2. The effect of the layer sequence, individual layer thickness and deposition temperature on the structural and electrical properties of the laminates were investigated. It is found that the layer sequence of the laminates affects the crystallinity of the layers and changes the electrical properties. The amorphous laminate with a CeO{sub}2 starting layer with 4 nm physical thickness and an EOT of 2 nm, has the lowest J@V{sub}(fb)-1 V=1.88 × 10{sup}(-7) A/cm{sup}2. The best EOT-J{sub}g trade off is achieved by the laminated layers with a CeO{sub}2 starting layer deposited at 520°C.