2D Materials Based on Chalcogenides MoS2 and WS2

The chalcogenides MoS₂ and WS₂ are used here as alternative semiconductor materials to silicon (2D-layer material). Instead of classical doping of silicon for n- or p-type semiconductors, contact with material of different work functions is used for work function tuning. The use of this material is characterized by very thin layers. Subsequent deposition and patterning steps enable 2D-integrated multi-level devices. Due to the small thickness (<= 2 nm), full depletion in vertical direction is guaranteed. Fraunhofer offers development of new components on base of these new materials and the adaption of standard CMOS-processing steps.

Sensors and Actuators

2D-bipolar structures for signal enhancement. Instead of lateral field effect transistor layout (FET) choice of vertical bipolar layout for signal amplification. This offers the opportunity to detect the electron exchange of surface reactions for sensing. Especially for highly polar media like water, which hides small polarity changes of reactions at FET layouts. 

Analog neuromorphic computing at the edge 

The hardware for the neurons for neuromorphic Computing can be realized using multi-terminal transistors.  The tunable discrimination levels of neurons are used for tunable output response.  In case of spiking neuron applications, inherent spike generation with MoS₂ or WS₂ is possible. Analog neuronal devices are related in design to the 2D-bipolar structures.

Fraunhofer EMFT offers the following services in this area:

• Application-specific development of devices
• Device design
• Structural and electrical characterization of materials and devices (performance analysis).
• No sub-contracting of layer deposition

Technology

On the equipment base, Fraunhofer EMFT contributes with a 3-chamber cluster tool, funded by „Bundesministerium für Bildung und Forschung, Germany“ (Project FMD, 16FMD01K). Mature wafer size is 200 mm, but with adapters processing of smaller wafers or samples is possible as well. With this, the basic research results can be transferred to a production related workflow. These three chambers enable the following fundamental processing types:

• Sulfurization of metallic layers (400 °C to 800 °C); inductively coupled plasma included
• Chemical-Vapour-Deposition (CVD)-processing (400 °C to 800 °C)
• Atomic Layer Deposition (ALD)-processing at lower temperature levels (200 °C to 550 °C); reactive ion and inductively coupled plasmas
• Atomic-Layer-Etch (ALE)-process; excitation of adsorbed etch gases by reactive ion impinchement

These competences in the area of 2D materials are available at Fraunhofer EMFT for your application topics. We look forward to hearing from you!