Richard van de Sanden

ALD Options for Si-integrated Ultrahigh-density Decoupling Capacitors in Pore and Trench Designs

This paper reviews the options of using Atomic Layer Deposition (ALD) in passive and heterogeneous integration. The miniaturization intended by both integration schemes aim at Si-based integration for the former and at die stacking in a compact System-in-Package for the latter. In future Si-based integrated passives a next miniaturization step in trench capacitors requires the use of multiple ‘classical’ MOS layer stacks and the use of so-called high-k dielectrics (based on HfO2, etc.) and novel conductive layers like TiN, etc. to compose MIS and MIM stacks in ‘trench’ and ‘pore’ capacitors with capacitance densities exceeding 200 nF/mm 2 . One of the major challenges in realizing ultrahigh-density trench capacitors is to find an attractive pore lining and filling fabrication technology at reasonable cost and reaction rate as well as low temperature (for back-end processing freedom). As the deposition for the dielectric and conductive layers should be highly uniform, step-conformal and lowtemperature (≤ 400 °C), ALD is an enabling technology here, by virtue of the self-limiting mechanism of this layer-by-layer deposition technique. This article discusses first a few examples of LPCVD deposition of conventional MOS layers with ONO-dielectrics and in situ doped polycrystalline silicon, both as single layers and multilayer stacks. In addition, a few options for ALD deposition of thin dielectric and conductive layers (e.g. HfO2- and TiN-based) will be discussed. The silicon substrates that were used contained high aspect ratio (≥ 20) features with cross-section and spacing of the order of 1 µm.

ELNES study of carbon K-edge spectra of plasma deposited carbon films

Electron energy loss spectroscopy was used to investigate the bonding of plasma deposited carbon films. The experimental conditions include the use of a specific collection angle for which the shape of the spectra is free of the orientation dependency usually encountered in graphite due to its anisotropic structure. The first quantification process of the energy loss near-edge structure was performed by a standard fit of the collected spectrum, corrected for background and multiple scattering, with three Gaussian functions followed by a comparison with the graphite spectrum obtained under equivalent experimental conditions. In a second approach a fitting model directly incorporating the background subtraction and multiple scattering removal was applied. The final numerical results are interpreted in view of the deposition conditions of the films and the actual fitting procedure with the related choice of parameters.

Special Issue of Papers by Plenary and Topical Invited Lecturers at the 22nd International Symposium on Plasma Chemistry (ISPC 22), 5–10 July 2015, Antwerp, Belgium: Introduction

The ISPC 22 was organised jointly by the University of Antwerp and the Dutch Institute for Fundamental Energy Research from July 5 till July 10, 2015, in the beautiful town of Antwerp at the city campus of the University of Antwerp. The conference, whose governing body is the International Plasma Chemistry Society, spans the full range of plasma chemistry and plasma processing research, from fundamentals to applications, both from academia as well as from industry. The programme included contributions from lowpressure, atmospheric-pressure non-equilibrium and thermal plasmas. Furthermore, the conference was preceded by an industrial workshop on ‘‘Re-use of CO2’’, which took place on Sunday July 5 at the University of Antwerp, as well as by an ISPC Summer school, which was hosted by DIFFER at its brand new location at the TU/e Science campus. In addition, the conference hosted the workshop on ‘‘Plasma-mediated effects on biological systems’’. This special issue, which we happily present, contains the papers by the plenary and topical invited lecturers of ISPC 22. The 22nd International Symposium on Plasma Chemistry was chaired by Prof. dr. Annemie Bogaerts of the University of Antwerp and Prof. dr. ir. Richard van de Sanden from DIFFER and Eindhoven University of Technology. The conference was sponsored by the University of Antwerp, DIFFER, Fund for Scientific Research Flanders and Wallonia– Brussels (FWO and FNRS), the Flemish Institute for Technological Research (VITO), Tekna Plasma Europe (Macon, France), AFS Entwicklungs ? Vertriebs GmbH (Horgau, Germany), InnoPhysics BV (Eindhoven, The Netherlands), Benelux Process bvba (Eke, Belgium), Bruker Belgium NV/SA (Evere, Belgium), Laser 2000 Benelux CV (Vinkeveen,

Non-equilibrium microwave plasma for efficient high temperature chemistry

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

Co2 conversion by plasmolysis: A route to solar fuels

Summary form only given. Sustainable energy generation by means of wind or from solar radiation through photovoltaics or concentrated solar power will be a significant part of the energy mix in 2025. Intermittency (due to e.g. day/night cycle) as well as regional variation of these energy sources requires means to store and transport energy on a large scale. A promising option is creating artificial solar fuels (or CO2 neutral fuels) with sustainable energy, which can easily be deployed within the present infrastructure for conventional fossil fuels. A candidate raw material would be CO2 itself (fitting in carbon capture and utilization, CCU, strategies). Presently, no efficient schemes are yet available for the conversion of CO2 into fuels. A plasma chemical approach potentially offers high energy efficiency (up to 90%) due to selectivity in the reaction processes that can be tailored via its inherently strong out-of-equilibrium processing conditions. At the same time, it is characterized by efficient and fast power switching, low investment costs, no scarce materials required, and high power density, which are all advantageous for addressing intermittency. In this presentation, the plasma chemical approach will be introduced and examples will be discussed of research carried out at the DIFFER to ultimately enable a scale up to industrial applications. In particular, a common microwave reactor approach is evaluated experimentally with Rayleigh scattering and Fourier transform infrared spectroscopy to assess gas temperatures (up to ~3000 K) and conversion degrees (up to 30%), respectively. The results are interpreted on basis of estimates of the plasma dynamics obtained with electron energy distribution functions calculated with a Boltzmann solver. It indicates that the intrinsic electron energies are higher than is favorable for preferential vibrational excitation due to dissociative excitation, which causes thermodynamic equilibrium chemistry still to dominate the initial experiments. Pulsing the power is shown to decrease gas temperatures and improve efficiency. Novel reactor approaches are proposed to tailor the plasma dynamics to achieve the non-equilibrium in which vibrational excitation is dominant.