Understanding the Origin of Metal Gate Work Function Shift and Its Impact on Erase Performance in 3D NAND Flash Memories

Micromachines

Attilio Belmonte¹  Jean-Philippe Soulié¹  Laurent Breuil¹  Ben Kaczer¹  Arjun Ajaykumar¹  Laura Nyns¹  Maarten Rosmeulen¹  Sivaramakrishnan Ramesh¹  Geert Van den bosch¹  Gabriel Khalil El Hajjam¹  Lars-Åke Ragnarsson¹ 

[1] IMEC, Kapeldreef 75, B-3001 Leuven, Belgium;

关键词: work function;    effective work function;    dipole;    metal gate;    high-k;    SiO₂;   

DOI  :  10.3390/mi12091084

来源: DOAJ

【 摘 要 】

We studied the metal gate work function of different metal electrode and high-k dielectric combinations by monitoring the flat band voltage shift with dielectric thicknesses using capacitance–voltage measurements. We investigated the impact of different thermal treatments on the work function and linked any shift in the work function, leading to an effective work function, to the dipole formation at the metal/high-k and/or high-k/SiO₂ interface. We corroborated the findings with the erase performance of metal/high-k/ONO/Si (MHONOS) capacitors that are identical to the gate stack in three-dimensional (3D) NAND flash. We demonstrate that though the work function extraction is convoluted by the dipole formation, the erase performance is not significantly affected by it.

【 授权许可】

Unknown