Rare-Earth Metal Scandate High-k Layers

Abstract

Ternary rare-earth metal scandate layers deposited using pulsed laser deposition (PLD) were studied as dielectrics for high-k applications. GdScO3, DyScO3 and LaScO3 blanket layers with different nominal thicknesses were deposited directly on 2-inch Si (100) substrates for physical characterizations and 2-inch substrates with a lateral SiO2 isolation structure, for capacitor formation with wet-etched electrodes. High- temperature X-ray diffraction (HT-XRD) and TEM reveal that DyScO3 and GdScO3 remain amorphous up to 1000C. The as- deposited DyScO3 layer on both 1nm chemical SiO2 and HF-last surface of Si shows good interface properties as revealed by C- V curves. The leakage current through the layers is comparable to or even lower than that through HfO2 layers of the same EOT. Material properties show sensitivity to annealing conditions.