Spectroscopic ellipsometry characterization of high-k gate stacks with Vt shift layers

• Published in: Thin solid films Vol. 519; no. 9; pp. 2889 - 2893
• Main Authors: Di, Ming, Bersch, Eric, Clark, Robert, Consiglio, Steven, Leusink, Gert, Diebold, Alain C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 28.02.2011; Elsevier
• Subjects: Capping layer; Condensed matter: structure, mechanical and thermal properties; Deposition; Dispersions; Ellipsometry; Exact sciences and technology; Film thickness; Hafnium oxide; HfO2; High-k dielectrics; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; La2O3; Optical instruments, equipment and techniques; Physics; Polarimeters and ellipsometers; Reflectivity; Spectroscopic ellipsometry; Spectroscopy; Stacks; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Vt shift layer; X-ray reflectivity; X-rays; HfO2; Spectroscopic ellipsometry; X-ray reflectivity; La2O3; High-k dielectrics; Film thickness; Capping layer; Vt shift layer; RBS; Angular resolution; Theoretical study; Hafnium oxide; X-ray reflection; Dispersions; Layer thickness; Lanthanum oxide; HfO; 0; La; Gallium tellurides; V; High k dielectric; Modelling; shift layer; Gates; X-ray photoelectron spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.12.060

We have used spectroscopic ellipsometry (SE) to measure layer thicknesses of HfO2/La2O3 and La2O3/HfO2 stacks on SiO2/p-Si. Two approaches to extract layer thicknesses from a single SE measurement were shown to be inaccurate, possibly due to similarities in the optical dispersions of HfO2 and La2O3. The approach where SE data was collected after deposition of each layer and only the thickness of the top layer was determined by modeling was found to be capable of accurately measuring the thickness of each layer. These conclusions are supported by angle resolved X-ray photoelectron spectroscopy (ARXPS), X-ray reflectivity (XRR) and Rutherford backscattering spectroscopy (RBS) measurements.