Thin-film Technologies

Research Topics

© Fraunhofer IISB

Fully Solution Processed Gate Stack developed in FP7 Project POINTS. Nanoparticle-based InZnO Semiconductor and Hybrid organic-inorganic Insulator integrated with Ink Jet printed silver Ink.

Inorganic thin films for large-area coating and printing are provided for functional electrodes and electronic applications.

Besides facile and low-cost processing, low temperature drying and conversion is a major research goal, making the films applicable to a wide range of substrates.

The targetted application fields functionalities include

  • optoelectronics
  • transparent conductive films, injection layers, insulators, encapsulants
  • energy systems
  • capacitor stacks, battery electrodes
  • integrated thin-film sensorics and electronics for industrial and automotive electronics, wearables / sports gear, and energy electronics
  • semiconductors, insulators, and conductors for thin-film transistors, functional films/stacks for resistive sensors or charge sensing devices

Research on thin-film materials is centered around the versatile chemical routes for the synthesis and deposition of metal oxide materials. Alternative materials systems as polymer or nanoparticle-based silicon, organic-inorganic compounds, and nanoscale metals round out the portfolio for serving manifold requests.

The extensive cleanroom facilities of IISB offer a broad range of conventional chemical (PECVD, ALD, LPCVD) and physical (Sputtering, e-beam evaporation) vapor deposition techniques for complementary referencing and benchmarking of materials and layer systems.

Services

Cooperation offers include:

  • contract-based bilateral research
  • partnering in publicly-funded research projects (see e.g. ROLL-OUT, POINTS, SuperLIB)
  • feasibility studies and consulting services for thin-film materials and large-area, printed-electronics applications

Please see specialized pages for system applications the thin-film systems group

Printed Electronics

© Fraunhofer IISB

Printed TFT Gate Electrodes

Printing of electronic materials opens up a range of novel low-cost, low complexity,and large-area components, circuits, and systems on alternative (e.g. flexible) substrates. Fully or partially printed devices include antennas for RFID, thick-film sensors, or displays.
IISB research in printed electronics is focused on inorganic materials from synthesis through to system integration.
A joint working group with the Chair of Electron Devices at University of Erlangen (FAU) covers basic and applied research topics.

Synthesis and Formulation

© Fraunhofer IISB

SEM Image of cubic CuO Particles, Inset: CuO-ink

Functional nano materials for printed electronics are synthesized by gas-phase or wet chemical chemistry.

Composition, size, and morphology of particles and/or layers can be widely modified with regard to processing (e.g. melting point) or electrical (e.g.bad gap) behavior.

Synthesis of doped semiconductor nanoparticles, ternary, or quaternary metal oxide systems is a promising research arena. Ink properties like viscosity, surface energy, and vapor pressures can be tailored with respect to subsequent processing. Thus, functional features can be produced by various techniques including ink jet printing, spray pyrolysis, and screen printing.

Structure Formation

© Fraunhofer IISB

Inkjet Printer for Materials Deposition and Ink Development

Inks and precursor solutions are processed into thin films and structures by spin-casting or various printing methods. Substrates, inks, and processing conditions have to be carefully adjusted to give best results with respect to critical dimensions and electrical performance of the devices.

The formation of highly ordered layers and interfaces is not only important for the electrical behavior ofthe layers but also for the ability to stack several layers on top of each other. Also thermal and chemical compatibility of subsequently deposited materials have to be taken into account.

Applications

© Fraunhofer IISB

Capacitive Touch Sensor

The developed inks and layer stacks are combined with commercially available materials into functional applications demonstrating the unique abilities of printed electronics.

Examples for printed functionalities are interdigitated metal structures as basis for capacitive or resistive sensors or thin-film transitor test structures for the study of device architectures and comparison of materials.

Device development is carried out in conjunction with the technological background of conventional semiconductor processing provided by the IISB/LEB cleanroom facility. Fully integrated systems include discrete devices, power supplies, as well as microprocessor ICs for signal and data processing.

Low Temperature Thin-Film Technologies

© Fraunhofer IISB

Low Temperature processed Thin Film Transistors based on Zinc Oxide

Sensitive substrates like technical glasses or plastics for display or lighting applications demand for low temperature deposition techniques. Aiming at system integration Fraunhofer IISB offers deposition services as well as R&D know-how for the improvement of thin-films and devices.

The team has long-term expertise in process and equipment development for physical (PVD) and chemical vapor deposition (CVD), the latter ranging from conventional low-pressure CVD through metal organic CVD to plasma-enhanced or atomic-layer deposition techniques. Recent projects include sputtering of metal oxides for use in thin-film transistors.

Silicon Process Integration

© Fraunhofer IISB

Silicon Wafer with Thermoelectric Generators based on doped Poly Silicon

Based on a range of lithographic techniques like proximity printing (mask aligner), laser, and e-beam writing and accompanying etching techniques, Fraunhofer IISB offers various opportunities for the development of application-specific micro- and nanoelectronics, -fluidics, and –mechanics applications. In addition to photolithographic structuring, several elaborated resist systems are further utilized for sealing of surfaces and temporary or permanent joining of wafers.

 

Thin-Film Systems

 

Pyrolytic Spray Coating

 

Functionality from Inks

Publications