Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Reaction Mechanisms during Plasma-assisted Atomic Layer Deposition

Figure 1: Schematic concept of the different diagnostics implemented in situ to obtain a fundamental understanding of the reaction mechanism of plasma-assisted ALD
Figure 1: Schematic concept of the different diagnostics implemented in situ to obtain a fundamental understanding of the reaction mechanism of plasma-assisted ALD

Abstract:
Dr Erik Langereis and Prof Erwin Kessels
Department of Applied Physics, Eindhoven University of Technology, The Netherlands

Reaction Mechanisms during Plasma-assisted Atomic Layer Deposition

UK | Posted on June 14th, 2010

Atomic layer deposition (ALD) is considered the primary candidate for growth of conformal films with thickness control on the atomic level. The technique derives its growth control by alternating (two) self-limiting adsorption reactions in order to ensure that a submonolayer of film is deposited per so-called ALD cycle. By selecting the appropriate amount of deposition cycles, the film thickness can be controlled with ultimate precision.

A novel ALD concept is to use a plasma to activate one of the reactants in the gas phase in order to provide additional reactivity to the surface chemistry. These plasma-assisted ALD processes are researched to allow for deposition at reduced temperatures, to realize improved and tunable film properties, and to increase the choice in chemistry and precursors. To obtain a fundamental understanding of the surface reactions taking place and to evaluate the merits of the use of a plasma, a systematic study on the reaction mechanism of plasma-assisted ALD has been carried out for the deposition of metaloxides, metal-nitrides, and noble metals (Fig. 1).

Especially at reduced substrate temperatures, plasma-assisted ALD of metal-oxides distinguishes itself by providing good quality films due to the reactivity delivered by an O2 plasma. By determination of the surface groups by transmission infrared (IR) spectroscopy [1] and the reaction by-products by the combination of mass spectrometry and optical emission spectroscopy (OES) [2], it has been established that the Al2O3 growth is driven by a combustion-like surface chemistry. This chemistry proceeds for depositions down to room temperature. At this low temperature, it is observed that the plasma exposure time is an effective means to optimize the film quality.

For plasma-assisted ALD of metal-nitrides, the reducing power of an H2 plasma is found to be key in depositing conductive films. Using a plasma provides, moreover, the opportunity to tailor the material properties of the film by controlling the plasma condition. For example, by varying the plasma exposure time and plasma gas composition, the TaNx film properties can be controlled from conductive TaN to semiconductive Ta3N5 as evident from spectroscopic ellipsometry [3,4].

Furthermore, for ALD of noble metals such as Pt and Ru, the nucleation and film closure can be improved considerably using a plasma, which can result in smoother and thinner applicable metal films [5]. The mechanisms and growth observations deduced from these studies are expected to be generic for equivalent plasma-assisted ALD processes.

[1] Langereis et al., Appl. Phys. Lett. 92, 231904 (2008).
[2] Heil et al., J. Appl. Phys. 103, 103302 (2008).
[3] Langereis et al., J. Appl. Phys. 102, 083517 (2007).
[4] Langereis et al., topical review in J. Phys. D.: Appl. Phys. 42, 073001 (2009)
[5] Knoops et al., Electrochem. Solid-State Lett. 12, G34 (2009).

####

For more information, please click here

Copyright © Oxford Instruments

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Unveiling the quantum necklace: Researchers simulate quantum necklace-like structures in superfluids May 26th, 2017

Thin films

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

MIT Energy Initiative awards 10 seed fund grants for early-stage energy research May 4th, 2017

Nanomechanics, Inc. Unveils New Product at ICMCTF Show April 25th: Nanoindentation experts will launch the new Gemini that measures the interaction of two objects that are sliding across each other not merely making contact April 21st, 2017

Nanomechanics Inc. President Warren Oliver, PhD to Present at ICMCTF: Nanoindentation experts will discuss new testing system that measures the interaction of two objects that are sliding across each other not merely making contact April 17th, 2017

Academic/Education

MIT Energy Initiative awards 10 seed fund grants for early-stage energy research May 4th, 2017

Bar-Ilan University to set up quantum research center May 1st, 2017

California Research Alliance by BASF establishes more than 25 research projects in three years April 26th, 2017

SUNY Polytechnic Institute Announces Total of 172 Teams Selected to Compete in Solar in Your Community Challenge: Teams from 40 states, plus Washington, DC, 2 Territories, and 4 American Indian Reservations, Will Deploy Solar in Underserved Communities April 20th, 2017

Announcements

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Unveiling the quantum necklace: Researchers simulate quantum necklace-like structures in superfluids May 26th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project