Laminated CeO2/HfO2 High-K Gate Dielectrics Grown by Pulsed Laser Deposition in Reducing Ambient

CeO2 and HfO2 dielectric layers were deposited in an Ar+(5%)H2 gas mixture by Pulsed Laser Deposition (PLD) on Si (100). A CeO2-Ce2O3 transformation is achieved by deposition in reducing ambient. It is also shown that in-situ post deposition anneal efficiently oxidizes Ce2O3 layers to CeO2. The properties of CeO2/HfO2 laminated structures deposited in reducing ambient are compared with binary oxide layers of CeO2 and HfO2. The effect of the layer sequence, individual layer thickness and deposition temperature on the properties of the laminates were investigated. It is found that the layer sequence affects the crystallinity of the laminates and changes their electrical properties. The amorphous laminate with a CeO2 starting layer with 4 nm physical thickness and an EOT of 2 nm, has the lowest J@Vfb 1V=1.88x10-7 A/cm2. The best EOT Jg trade off is achieved by the laminated layers with a CeO2 starting layer deposited at 520{degree sign}C