Atomic layer deposition of silicon nitride from novel precursor DSBAS and nitrogen plasma

The deposition of high-quality silicon nitride (SiNx) layers is required in the manufacturing of state-of-the-art field-effect transistors (FETs), which are used everywhere throughout modern computing. An important application of SiNx in FETs is as a side-wall gate spacer, where it functions as a barrier layer to protect sensitive inner layers, against for example oxygen ingress and etch processing steps. From a literature study further opportunities and applications of SiNx films in future three-dimensional FET architectures will be discussed. It will be shown that a low thermal budget is essential for these applications of SiNx, in addition to obtaining a high quality and a high conformality. A novel precursor Di(Sec-Butyl)AminoSilane (DSBAS, SiH3N(C4H9)2) was employed to develop a plasma-assisted atomic layer deposition (ALD) process to grow high-quality SiNx at low substrate temperatures. Material properties have been characterised over a wide temperature range and have been compared with properties of a similar organosilane precursor Bis(Tert-Butyl-Amino)Silane (BTBAS, SiH2[NH(C4H9)]2). Compared to the BTBAS process and other plasma-assisted ALD processes reported in the literature, the obtained growth per cycle was low. However, typically high-quality SiNx films were obtained as was demonstrated by low wet etch-rates, low C, O, and H content, high mass densities and N/Si values close to stoichiometric Si3N4. The high-quality of the SiNx was also investigated in trenches with aspect ratio 1:4.5, relevant for FET applications. High quality was confirmed at horizontal surfaces in the trench, while at vertical surfaces the quality was slightly poorer. However, the conformality was proven to be not sufficient. The reduced thickness and quality at vertical side-walls also suggest that ions play a role in the quality and growth of SiNx films.The results in this work provide support for a growth mechanism, previously proposed for BTBAS. This mechanism explains how the split-off of the only amino-ligand in a DSBAS-molecule in the precursor half-cycle, reduces redeposition of ligand fragments in the subsequent plasma half-cycle leading to high film quality. The new insights obtained in this work have resulted in new proposed experiments, in order to further investigate the reaction mechanisms involved. The deposition of high-quality silicon nitride (SiNx) layers is required in the manufacturing of state-of-the-art field-effect transistors (FETs), which are used everywhere throughout modern computing. An important application of SiNx in FETs is as a side-wall gate spacer, where it functions as a barrier layer to protect sensitive inner layers, against for example oxygen ingress and etch processing steps. From a literature study further opportunities and applications of SiNx films in future three-dimensional FET architectures will be discussed. It will be shown that a low thermal budget is essential for these applications of SiNx, in addition to obtaining a high quality and a high conformality. A novel precursor Di(Sec-Butyl)AminoSilane (DSBAS, SiH3N(C4H9)2) was employed to develop a plasma-assisted atomic layer deposition (ALD) process to grow high-quality SiNx at low substrate temperatures. Material properties have been characterised over a wide temperature range and have been compared with properties of a similar organosilane precursor Bis(Tert-Butyl-Amino)Silane (BTBAS, SiH2[NH(C4H9)]2). Compared to the BTBAS process and other plasma-assisted ALD processes reported in the literature, the obtained growth per cycle was low. However, typically high-quality SiNx films were obtained as was demonstrated by low wet etch-rates, low C, O, and H content, high mass densities and N/Si values close to stoichiometric Si3N4. The high-quality of the SiNx was also investigated in trenches with aspect ratio 1:4.5, relevant for FET applications. High quality was confirmed at horizontal surfaces in the trench, while at vertical surfaces the quality was slightly poorer. However, the conformality was proven to be not sufficient. The reduced thickness and quality at vertical side-walls also suggest that ions play a role in the quality and growth of SiNx films.The results in this work provide support for a growth mechanism, previously proposed for BTBAS. This mechanism explains how the split-off of the only amino-ligand in a DSBAS-molecule in the precursor half-cycle, reduces redeposition of ligand fragments in the subsequent plasma half-cycle leading to high film quality. The new insights obtained in this work have resulted in new proposed experiments, in order to further investigate the reaction mechanisms involved

Editorial independence in an automated media system

The media has increasingly grown to rely on automated decision-making to produce and distribute news. This trend challenges our understanding of editorial independence by transforming the role of human editorial judgment and creating new dependencies on external software and data providers, engineers, and platforms. Recent policy initiatives such as the EU’s Media Action Plan and Digital Services Act are now beginning to revisit the way law can enable the media to act independently in the context of new technological tools and actors. Fully understanding and addressing the challenges automation poses to editorial independence, however, first requires better normative insight into the functions editorial independence performs in European media policy. This article provides a normative framework of editorial independence’s functions in European media policy and uses it to explore the new challenges posed by the automation of editorial decision-making

Sustainability and indicators in Amazonia : conceptual framework for use in Amazonia

This report outlines issues of sustainable development and its measurement which can be relevant for use in the PanAmazonian Countries (PAC). It reviews concepts of sustainability that have been formulated both in the political and scientific worlds and attempts to apply them to specific issues that can be relevant for assessing sustainable development in the PAC. The report emphasises the various ways in which sustainable development can be defined and measured. It describes the evolution of the concept of sustainable development in both the political and scientific arena. Many different definitions and operationalisations of the concept of sustainable development come to the foreground. However, there does not exist a methodology that can scientifically prove which conception or operationalisation is to be preferred above the other ones. More problems arise when sustainable development is to be measured by indicators. Indicators schemes that have been provided in the literature seem to be defined ad-hoc at best. For the study area of Amazonia, the report suggests that the Agenda 21 indicators can be a useful element in future studies. The precise set of indicators to be used depends also on the sustainability patterns to be investigated (economic sectors, regions, communities), the availability and reliability of the data necessary to construct the indicators, and the questions we want to answer

The adventure of greening the University : rol van het studentennetwerk Morgen bij kennisuitwisseling voor duurzame ontwikkeling binnen het hoger onderwijs

De Wetenschapswinkel heeft in opdracht van het studentennetwerk Morgen een onderzoeksproject uitgevoerd naar duurzame ontwikkeling binnen universiteiten en hogescholen. Het doel van het project ‘The Adventure of Greening the University’ is om ‘Morgen’ te adviseren hoe het proces van kennisuitwisseling rondom duurzame ontwikkeling binnen het hoger onderwijs te versnellen

The EU is going too far with political advertising

The EU is set to complement the DSA with a new regulation on (targeted) political advertisements. In this piece we highlight how the regulation’s definition of political advertisements and enforcement mechanisms threaten freedom of expressio