Presentation
Thin film deposition and patterning is a key challenge in device miniaturisation and the implementation of novel functionalities. Complex oxide materials have long been considered as very promising because they exhibit a wide range of properties not to be found easily in other materials. However, the production of structured high quality films of complex oxides is still very challenging. We are proposing a new vision in thin film deposition that will associate effectively cost optimisation, flexibility and sustainability based on a Laser-Assisted Chemical Beam Epitaxy (LACBE) process with the following features:
  • high quality films,
  • epitaxial growth,
  • controlled stoichiometry,
  • 3D patterning.
Laser-Assisted Chemical Beam Epitaxy may well be the key to provide the future device requirements that today's methods can not address. Laser-Assisted Chemical Beam Epitaxy will allow to grow multi-component oxides with 3D patterning of properties during the growth in only one step (3D selective and graded properties at the micrometre and nanometre scale).

In particular, the objective of 3D-DEMO is to study the growth of complex oxide thin films for electro-optic and piezoelectric applications. 3D-DEMO will develop hardware and processes for Chemical Beam Epitaxy (CBE) to
  • achieve good film uniformities on 100 to 150 mm wafers,
  • allow for systematic stoichiometric variations in combinatorial research,
  • allow for in-situ structured growth by laser assistance.
Pulsed laser deposition (PLD) - a technique for small samples only - is used as complimentary method in order to advance faster in materials and characterisation knowledge (National Institute for Lasers, Plasma and Radiation Physics). Functionality will be evaluated by means of test devices demonstrating optical and electro-optical properties in wave guiding (1.5 µm), frequency doubling, and wave trapping in ring oscillators (University of Southampton, EPFL, CNRS); and piezoelectric properties in bulk acoustic wave resonators (EPFL). On a microscopic level, Scanning Near-field Optical Microscopy (SNOM) will be employed to study optical uniformity and patterned features (CNRS). The novel film deposition hardware is developed by the Swiss SME ABCD Technology. The project includes two more large industrial partners for providing optimized CVD precursors (SAFC) and full characterised state-of-the art substrates (SAES Getters) of LiNbO3 (LN) and LiTaO3 (LT). These substrates are ideal to combine the new thin films with existing technology based on LN and LT single crystals. It is intended to include ferroelectric domain engineering, eventually including selectively etched structures, in our studies.

The first major milestone of the project is the development of the new thin film deposition technique (LACBE) to achieve direct 3D patterning of the film properties in only one step during the growth (selective growth, selective doping, graded indexes).

The second major milestone will be to fully characterise by combinatorial deposition a whole material family (LiNO3 pure and doped, and new close similar materials like SrxBa1-xNb2O6 (SBN) and [Na,K)(Nb,Ta)O3]1-x[LiNbO3]x (x < 0.1)) with the ability to fine tune the properties for future applications.

The final goal of 3D-DEMO will be to investigate the integration of many functions on one single device with material properties patterning during the growth, allowing vertical integration.

Find out more about the 3D-DEMO partners here.