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.

Method for hafnium nitride deposition

Abstract: The present invention generally is a method for forming a high-k dielectric layer, comprising depositing a hafnium compound by atomic layer deposition to a substrate, comprising, delivering a hafnium precursor to a surface of the substrate, reacting the hafnium precursor and forming a hafnium containing layer to the surface, delivering a nitrogen precursor to the hafnium containing layer, forming at least one hafnium nitrogen bond and depositing the hafnium compound to the surface.

Low temperature plasma-enhanced atomic layer deposition of metal oxide thin films

Abstract: Many reported atomic layer deposition (ALD) processes are carried out at elevated temperatures (>150°C), which can be problematic for temperature-sensitive substrates. Plasma-enhanced ALD routes may provide a solution, as the ALD temperature window can, in theory, be extended to lower deposition temperatures due to the reactive nature of the plasma. As such, the plasma-enhanced ALD of Al 2 O 3 , TiO 2 , and Ta 2 O 5 has been investigated at 25-400°C using [Al(CH 3 ) 3 ], [Ti(O i Pr) 4 ], [Ti(Cp Me )(O i Pr) 3 ], [TiCp*(OMe) 3 ], and [Ta(NMe 2 ) 5 ] as precursors. An O 2 plasma was employed as the oxygen source in each case. We have demonstrated metal oxide thin-film deposition at temperatures as low as room temperature and compared the results with corresponding thermal ALD routes to the same materials. The composition of the films was determined by Rutherford backscattering spectroscopy. Analysis of the growth per cycle data and the metal atoms deposited per cycle revealed that the growth per cycle is strongly dependent on the film density at low deposition temperatures. Comparison of these data for Al 2 O 3 ALD processes in particular, showed that the number of Al atoms deposited per cycle was consistently high down to room temperature for the plasma-enhanced process but dropped for the thermal process at substrate temperatures lower than 250°C.

Enhanced atomic layer deposition

Abstract: A method of enhanced atomic layer deposition is described. In an embodiment, the enhancement is the use of plasma. Plasma begins prior to flowing a second precursor into the chamber. The second precursor reacts with a prior precursor to deposit a layer on the substrate. In an embodiment, the layer includes at least one element from each of the first and second precursors. In an embodiment, the layer is TaN. In an embodiment, the precursors are TaF 5 and NH 3 . In an embodiment, the plasma begins during the purge gas flow between the pulse of first precursor and the pulse of second precursor. In an embodiment, the enhancement is thermal energy. In an embodiment, the thermal energy is greater than generally accepted for ALD (>300 degrees Celsius). The enhancement assists the reaction of the precursors to deposit a layer on a substrate.

High densities of magnetic nanoparticles supported on graphene fabricated by atomic layer deposition and their use as efficient synergistic microwave absorbers

Abstract: An atomic layer deposition (ALD) method has been employed to synthesize Fe3O4/graphene and Ni/graphene composites. The structure and microwave absorbing properties of the as-prepared composites are investigated. The surfaces of graphene are densely covered by Fe3O4 or Ni nanoparticles with a narrow size distribution, and the magnetic nanoparticles are well distributed on each graphene sheet without significant conglomeration or large vacancies. The coated graphene materials exhibit remarkably improved electromagnetic (EM) absorption properties compared to the pristine graphene. The optimal reflection loss (RL) reaches −46.4 dB at 15.6 GHz with a thickness of only 1.4 mm for the Fe3O4/graphene composites obtained by applying 100 cycles of Fe2O3 deposition followed by a hydrogen reduction. The enhanced absorption ability arises from the effective impedance matching, multiple interfacial polarization and increased magnetic loss from the added magnetic constituents. Moreover, compared with other recently reported materials, the composites have a lower filling ratio and smaller coating thickness resulting in significantly increased EM absorption properties. This demonstrates that nanoscale surface modification of magnetic particles on graphene by ALD is a very promising way to design lightweight and high-efficiency microwave absorbers.