Atomic layer deposition

About: Atomic layer deposition is a research topic. Over the lifetime, 19821 publications have been published within this topic receiving 477332 citations. The topic is also known as: ALD.

Plasma-enhanced atomic layer deposition of Ta and Ti for interconnect diffusion barriers

Abstract: Thin films of inert, refractory materials are used in semiconductor interconnect applications as diffusion barriers, seed, and adhesion layers. A typical example is the use of a thin, conformal Ta or Ti/TiN films on the walls of a dielectric trench or via which reduces or eliminates out-diffusion of the primary conductor, usually Cu, into the dielectric. Atomic layer deposition is a known technique which is intrinsically conformal and is appropriate for this application. Plasma enhancement of the process allows deposition at significantly lower temperatures than conventional chemical vapor deposition, which is a requirement for low-k dielectrics. Tantalum films deposited at 25–400 °C using ALD with a TaCl5 precursor and atomic hydrogen as the reactive species at up to a rate of 1.67 Ang/cycle are amorphous, conformal, and show moderate or controllable levels of impurities; primarily oxygen and a small level of Cl. Similar results have been observed for Ti using TiCl4 as a precursor. The process scales to manufacturing dimensions and applications and will facilitate the extension of interconnect technology beyond (below) 100 nm dimensions.Thin films of inert, refractory materials are used in semiconductor interconnect applications as diffusion barriers, seed, and adhesion layers. A typical example is the use of a thin, conformal Ta or Ti/TiN films on the walls of a dielectric trench or via which reduces or eliminates out-diffusion of the primary conductor, usually Cu, into the dielectric. Atomic layer deposition is a known technique which is intrinsically conformal and is appropriate for this application. Plasma enhancement of the process allows deposition at significantly lower temperatures than conventional chemical vapor deposition, which is a requirement for low-k dielectrics. Tantalum films deposited at 25–400 °C using ALD with a TaCl5 precursor and atomic hydrogen as the reactive species at up to a rate of 1.67 Ang/cycle are amorphous, conformal, and show moderate or controllable levels of impurities; primarily oxygen and a small level of Cl. Similar results have been observed for Ti using TiCl4 as a precursor. The process scales to ...

In Situ Transmission Electron Microscopy Observation of Pulverization of Aluminum Nanowires and Evolution of the Thin Surface Al2O3 Layers during Lithiation–Delithiation Cycles

Abstract: Lithiation-delithiation cycles of individual aluminum nanowires (NWs) with naturally oxidized Al(2)O(3) surface layers (thickness 4-5 nm) were conducted in situ in a transmission electron microscope. Surprisingly, the lithiation was always initiated from the surface Al(2)O(3) layer, forming a stable Li-Al-O glass tube with a thickness of about 6-10 nm wrapping around the NW core. After lithiation of the surface Al(2)O(3) layer, lithiation of the inner Al core took place, which converted the single crystal Al to a polycrystalline LiAl alloy, with a volume expansion of about 100%. The Li-Al-O glass tube survived the 100% volume expansion, by enlarging through elastic and plastic deformation, acting as a solid electrolyte with exceptional mechanical robustness and ion conduction. Voids were formed in the Al NWs during the initial delithiation step and grew continuously with each subsequent delithiation, leading to pulverization of the Al NWs to isolated nanoparticles confined inside the Li-Al-O tube. There was a corresponding loss of capacity with each delithiation step when arrays of NWs were galvonostatically cycled. The results provide important insight into the degradation mechanism of lithium-alloy electrodes and into recent reports about the performance improvement of lithium ion batteries by atomic layer deposition of Al(2)O(3) onto the active materials or electrodes.

Nanoscopic Patterned Materials with Tunable Dimensions via Atomic Layer Deposition on Block Copolymers

Abstract: Selective self-limited interaction of metal precursors with self-assembled block copolymer substrates, combined with the unique molecular-level management of reactions enabled by the atomic layer deposition process, is presented as a promising controllable way to synthesize patterned nanomaterials (e.g., Al{sub 2}O{sub 3} see Figure, TiO{sub 2}, etc.) with uniform and tunable dimensions.

Method of forming material using atomic layer deposition and method of forming capacitor of semiconductor device using the same

Abstract: Disclosed are methods of forming dielectric materials using atomic layer deposition (ALD) and methods of forming dielectric layers from such materials on a semiconductor device. The ALD process utilizes a first reactant containing at least one alkoxide group that is chemisorbed onto a surface of a substrate and then reacted with an activated oxidant that contains no hydroxyl group to form a dielectric material exhibiting excellent step coverage and improved leakage current characteristics.

Dielectric interface films and methods therefor

Abstract: An ultrathin aluminum oxide and lanthanide layers, particularly formed by an atomic layer deposition (ALD) type process, serve as interface layers between two or more materials. The interface layers can prevent oxidation of a substrate and can prevent diffusion of molecules between the materials. In the illustrated embodiments, a high-k dielectric material is sandwiched between two layers of aluminum oxide or lanthanide oxide in the formation of a transistor gate dielectric or a memory cell dielectric. Aluminum oxides can serve as a nucleation layer with less than a full monolayer of aluminum oxide. One monolayer or greater can also serve as a diffusion barrier, protecting the substrate from oxidation and the high-k dielectric from impurity diffusion. Nanolaminates can be formed with multiple alternating interface layers and high-k layers, where intermediate interface layers can break up the crystal structure of the high-k materials and lower leakage levels.