Depth profiling of very thin HfO2/Al2O3 stacks by ellipsometry. Issue 1 (1st March 2022)

• Record Type: Journal Article
• Authors: Karmakov, Y; Paskaleva, A; Spassov, D
• Is Part Of: Journal of physics. Volume 2240:Issue 1(2022)
• Publication Date: 2022-03-01
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/2240/1/012049
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Ellipsometry (VASE and MAIE) with appropriate algorithms for experimental data interpretation was applied for quantitative characterization of thin Al2 O3 /HfO2 multilayers formed by atomic layer deposition (ALD) applicable to the fabrication of charge-trapping nonvolatile memories. A substantial benefit of the algorithms is the depth profiling of the stacks. In this work, the depth profiles were retrieved of the HfO2 constituent in very thin (Al2 O3 :HfO2 ) stacks embedded in thin Al2 O3 surrounding layers. The peculiarities in the achieved depth profiles are used to determine the bi-layer blocks and their sub-layer thicknesses. The influence of a rapid thermal annealing in O2 on the depth profile and the sub-layer thicknesses is studied; substantial changes are thus revealed in the thickness and composition of the stacks. This information could be used in optimizing the dielectric and electrical properties of the stacks and multilayers.