Controlling the TiN Electrode Work Function at the Atomistic Level: A First Principles Investigation

Abstract

The paper reports on a theoretical description of work function of TiN, which is one of the most used materials for the realization of electrodes and gates in CMOS devices. Indeed, although the work function is a fundamental quantity in quantum mechanics and also in device physics, as it allows the understanding of band alignment at heterostructures and gap states formation at the metal/semiconductor interface, the role of defects and contaminants is rarely taken into account. Here, by using first principles simulations, we present an extensive study of the work function dependence on nitrogen vacancies and surface oxidation for different TiN surface orientations. The results complement and explain a number of existent experimental data, and provide a useful tool to tailoring transport properties of TiN electrodes in device simulations.

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

“…W Ref represents the CVD W/thin (3 nm) ALD TiN/Al 2 O 3 liner stack similar to the one used currently in 3D NAND production. We could note that the WF of TiN in combination with Al 2 O 3 is estimated to be about 4.53 eV and is in close agreement with the actual TiN WF reported in the literature [ 27 , 28 ]. What is surprising is the WF of Ru in combination with Al 2 O 3 , which is about 200–300 meV less than those reported in the literature for Ru metal [ 29 , 30 ].…”

“…However, it is possible to avert this interfacial reaction by using appropriate interfacial layer (IL), as can be seen from Figure 10. The WF of Ru improves to 4.8 eV by adding a thin (3 nm) TiN WF reported in the literature [27,28]. What is surprising is the WF of Ru in combination with Al2O3, which is about 200-300 meV less than those reported in the literature for Ru metal [29,30].…”

Descriptor engineering in machine learning regression of electronic structure properties for 2D materials

“…Figure 7 shows the bandgap and work-function predictions of the two types of 2D materials (conductors and semiconductors). The filled areas depict the values of band gap and work function of these materials reported in the literature and obtained mostly by costly computation 37 – 45 . We set an error range of 0.3 eV represented by the filled areas for a straightforward comparison with our ML approach.…”

Filament Formation in TaOx Thin Films for Memristor Device Application: Modeling Electron Energy Loss Spectra and Electron Transport

“…[ 38 ] Nonetheless, TiN‐based electrodes and gate contacts are typically polycrystalline, whose constituting grains have different sizes and expose multiple facets, which depend on the conditions and techniques used to grow the sample. [ 39 ] Here, we chose the Ta[100] and TiN[100] surfaces to minimize the strain at the interface. To build the interface, we generated slabs of Ta[100] and TiN[100] with four layers, as well as a unit cell of a Ta 2 O 5 slab, considering both crystalline and amorphous structures, that is, c Ta 48 O 120 and a Ta 48 O 120 .…”