The effect of lanthanum (La) incorporation in ultra-thin ZrO2 high-κ gate dielectrics

Metal-oxide-semiconductor (MOS) capacitors with La-incorporated ZrO2 (ZrLaO) high-κ gate dielectrics through co-sputtering technique have been fabricated. The effect of La incorporation on the thermal stability and electrical characteristics has been investigated. XRD spectra and HRTEM images indicate that the addition of La into ZrO2 can significantly increase the crystallization temperature of the films and inhibit the formation of interfacial layers. The technique of combined method of ellipsometer and XRR confirms that the interfacial layer is dramatically reduced with La incorporation, and the interfacial layer is identified as silicate formation through XPS depth profile. In addition, current–voltage and capacitance–voltage characteristics reveal that the relative dielectric constant and flatband voltage shift of MOS with ZrLaO dielectrics are improved with a slight reduction in barrier height.

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► The effect of La incorporation into ZrO2 high-κ gate dielectrics of MOS capacitors is investigated.
► The addition of La can significantly increase the crystallization temperature of ZrO2 films and inhibit the growth of interfacial layers.
► The dielectric constant and flatband voltage shift of MOS capacitors with La-incorporated ZrO2 are also improved.