AVS 60th International Symposium and Exhibition
    Electronic Materials and Processing Tuesday Sessions
       Session EM+MI+NS+SS+TF-TuA

Paper EM+MI+NS+SS+TF-TuA2
Investigation of Sub-Gap Defect States in High-k Dielectric Materials Using Reflection Electron Energy Loss Spectroscopy

Tuesday, October 29, 2013, 2:20 pm, Room 101 B

Session: High-k Oxides for MOSFETs and Memory Devices II/Oxides and Dielectrics for Novel Devices and Ultra-dense Memory I
Presenter: B. French, Intel Corporation
Authors: B. French, Intel Corporation
S.W. King, Intel Corporation
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The electrical reliability of high-k metal gate transistors is a growing concern as the nano-electronics industry moves to sub-12 nm dimensions and new 3D multi gate transistor technologies. In order to understand the various possible reliability failure mechanisms in high-k dielectric devices, knowledge of the band gap and defect states in high-k dielectrics is needed, but experimental identification of both the chemical identity and energy level of the defects contributing to reliability issues in high-k materials has gone largely unreported in many cases. In this regard, we have utilized Reflection Electron Energy Loss Spectroscopy (REELS) to determine the band gap of numerous single crystalline and amorphous high-k dielectric materials. We demonstrate that for standard single crystalline materials such as Quartz, Al2O3, and TiO2 REELS band gap measurements agree with known values. For amorphous high-k thin film materials, we further demonstrate that REELS band gap measurements in most cases agree with optical measurements of the same materials. However, in some cases, we have observed that REELS analysis is complicated by the existence of defect states within the band gap of these materials. While troublesome for band gap measurements, we demonstrate that this sensitivity can be utilized to determine the energy level of various defects in pristine and sputter damaged high-k dielectrics and in some cases the chemical identity of the defect can be determined.