In this article, Er-doped HfO2 high-k dielectrics (with similar to 4 and 7% Er) were prepared by atomic layer deposition, and their electrical and physical properties were studied. With the incorporation of a small amount of Er (up to 7% in this work), it is observed that (i) the work function of devices (TiN metal gate) can be modulated toward the Si conduction bandedge and that (ii) the thermal stability of the HfO2 film is improved, as evidenced by X-ray photoelectron spectroscopy and X-ray diffraction studies. In addition, the k-value and leakage properties of Er-doped HfO2 are comparable to those of HfO2. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3266877] All rights reserved.