Self-limited layer-by-layer etching of Si by alternated chlorine adsorption and Ar+ ion irradiation

Mizutani, Takashi; Murota, Junichi; Sawada, Yasuji; Ohmi, Tadahiro

doi:10.1063/1.110340

Cited by 108 publications

(73 citation statements)

References 5 publications

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“…Upon increasing substrate bias voltage, the etch rates increased rapidly with increased amounts of higher-order etch products (SiCl 3 , SiCl 4 ). Matsuura et al 22 and Suzue et al 32 reported on "self-limited layer-by-layer etching" and "selflimited atomic layer etching" of Si, respectively, using ECR plasmas. The etch rate per cycle increased with the chlorine exposure time and saturated to a constant value of about 1 2 and 1 3 of a monolayer per cycle for Si(100) for Si(111), respectively, independent of the chlorine partial pressure.…”

Section: The Early Days Of Atomic Layer Etchingmentioning

confidence: 99%

“…Steps 2 and 4 are purge steps. Since then, a large set of publications has appeared in scientific literature and the method has come to be known by a variety of other names, namely digital etching, 21 layer-by-layer etching, 22 molecular-layer etching, 23 plasma atomic layer etching (PALE), 24 etc. Yet, the original name of "atomic layer etching" coined in the first patent has remained most popular.…”

Section: The Early Days Of Atomic Layer Etchingmentioning

confidence: 99%

See 1 more Smart Citation

Atomic Layer Etching: What Can We Learn from Atomic Layer Deposition?

Faraz

Roozeboom

Knoops

et al. 2015

ECS J. Solid State Sci. Technol.

126

106

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Current trends in semiconductor device manufacturing impose extremely stringent requirements on nanoscale processing techniques, both in terms of accurately controlling material properties and in terms of precisely controlling nanometer dimensions. To take nanostructuring by dry etching to the next level, there is a fast growing interest in so-called atomic layer etching processes, which are considered the etching counterpart of atomic layer deposition processes. In this article, past research efforts are reviewed and the key defining characteristics of atomic layer etching are identified, such as cyclic step-wise processing, self-limiting surface chemistry, and repeated removal of atomic layers (not necessarily a full monolayer) of the material. Subsequently, further parallels are drawn with the more mature and mainstream technology of atomic layer deposition from which lessons and concepts are extracted that can be beneficial for advancing the field of atomic layer etching.

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Section: The Early Days Of Atomic Layer Etchingmentioning

confidence: 99%

Section: The Early Days Of Atomic Layer Etchingmentioning

confidence: 99%

Atomic Layer Etching: What Can We Learn from Atomic Layer Deposition?

Faraz

Roozeboom

Knoops

et al. 2015

ECS J. Solid State Sci. Technol.

126

106

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“…Versions of these tests have appeared in ALE studies, 39,47,48 although not necessarily called out or in context to one another. These tests can help indicate to what degree the ALE process approaches ideal behavior, albeit nonideal conditions may still yield significant benefit.…”

Section: Characterization Testsmentioning

confidence: 99%

Overview of atomic layer etching in the semiconductor industry

Kanarik¹,

Lill²,

Hudson³

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

469

372

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Atomic layer etching (ALE) is a technique for removing thin layers of material using sequential reaction steps that are self-limiting. ALE has been studied in the laboratory for more than 25 years. Today, it is being driven by the semiconductor industry as an alternative to continuous etching and is viewed as an essential counterpart to atomic layer deposition. As we enter the era of atomic-scale dimensions, there is need to unify the ALE field through increased effectiveness of collaboration between academia and industry, and to help enable the transition from lab to fab. With this in mind, this article provides defining criteria for ALE, along with clarification of some of the terminology and assumptions of this field. To increase understanding of the process, the mechanistic understanding is described for the silicon ALE case study, including the advantages of plasma-assisted processing. A historical overview spanning more than 25 years is provided for silicon, as well as ALE studies on oxides, III–V compounds, and other materials. Together, these processes encompass a variety of implementations, all following the same ALE principles. While the focus is on directional etching, isotropic ALE is also included. As part of this review, the authors also address the role of power pulsing as a predecessor to ALE and examine the outlook of ALE in the manufacturing of advanced semiconductor devices.

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“…For chlorine adsorption on a room temperature silicon substrate, Langmuir self-limited adsorption of about one monolayer of chlorine is typically seen. 81,82 Matsuura et al 83 found a self-limited layer-by-layer etching mechanism with the substrate at room temperature using Cl 2 exposure followed by low energy (20 eV) Ar ion bombardment in an ECR system. An etch depth of 0.5 atomic layer per cycle was achieved which increased with Cl 2 exposure of the surface.…”

Section: Iii-v: Gaasmentioning

confidence: 99%

Atomic Layer Etching at the Tipping Point: An Overview

Oehrlein

Metzler

2015

ECS J. Solid State Sci. Technol.

225

162

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The ability to achieve near-atomic precision in etching different materials when transferring lithographically defined templates is a requirement of increasing importance for nanoscale structure fabrication in the semiconductor and related industries. The use of ultra-thin gate dielectrics, ultra thin channels, and sub-20 nm film thicknesses in field effect transistors and other devices requires near-atomic scale etching control and selectivity. There is an emerging consensus that as critical dimensions approach the sub-10 nm scale, the need for an etching method corresponding to Atomic Layer Deposition (ALD), i.e. Atomic Layer Etching (ALE), has become essential, and that the more than 30-year quest to complement/replace continuous directional plasma etching (PE) methods for critical applications by a sequence of individual, self-limited surface reaction steps has reached a crucial stage. A key advantage of this approach relative to continuous PE is that it enables optimization of the individual steps with regard to reactant adsorption, self-limited etching, selectivity relative to other materials, and damage of critical surface layers. In this overview we present basic approaches to ALE of materials, discuss similarities/crucial differences relative to thermal and plasma-enhanced ALD, and then review selected results on ALE of materials aimed at pattern transfer. The overview concludes with a discussion of opportunities and challenges ahead. A requirement of increasing importance for nanoscale device fabrication is the ability to achieve atomic scale etching control and materials selectivity during pattern transfer.1-8 An etching method corresponding to Atomic Layer Deposition (ALD), i.e. Atomic Layer Etching (ALE), is expected to satisfy these needs as critical dimensions continue to shrink below the 10 nm scale.Demonstrations of self-limited dry etching methods capable of near-atomic resolution have a long history in the dry etching community and a brief review will be presented below. Key challenges for these approaches have been specialized equipment, long process times and low throughput.9,10 However, a recent demonstration using a commercial plasma etch tool 10 and activities within the dry etching community 11 provide indications that the situation has changed, and that we may have reached for ALE the Tipping Point which Gladwell defined as the "the moment of critical mass, the threshold, the boiling point" when "ideas and products and messages and behaviors spread like viruses do".12 This is due to several factors, including unprecedented demands on dry etching technology introduced by the semiconductor device evolution according to Moore's law that can be satisfied by atomic layer etching, advanced capabilities in plasma etch, and the existence of a critical level of information on plasma etch and ALD methods as applied in the semiconductor fabrication space.In this article we will provide a review of background of these approaches, and focus on issues that have to be overcome for widespread implement...

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Self-limited layer-by-layer etching of Si by alternated chlorine adsorption and Ar+ ion irradiation

Cited by 108 publications

References 5 publications

Atomic Layer Etching: What Can We Learn from Atomic Layer Deposition?

Atomic Layer Etching: What Can We Learn from Atomic Layer Deposition?

Overview of atomic layer etching in the semiconductor industry

Atomic Layer Etching at the Tipping Point: An Overview

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