The NMD group are embedded within Tyndall-UCC’s Micro-Nano-Systems (MNS) centre and are focused on designing and developing novel methods and processes for realising the next generation of electronic devices using emerging material systems and new device architectures. The research activities span across a wide range of areas aiming to achieve improved device energy-efficiency or low power device operation or high device performance. Monolithic 3D integration of new materials for digital circuitry, or digital and analogue circuitry together, is also an area of strong interest. The NMD group develops and implements advanced electrical characterisation methods to better understand these emerging material and device properties.
The group’s focus is on the design, development, electrical characterisation, and understanding of the gate stack and source/drain contact regions of novel metal-oxide-semiconductor field-effect transistor (MOSFET) devices employing emerging materials and forming advanced device structures that can give accurate insight into the device energy-efficiency and electrical performance. Applications of this research activity are many but include nanoelectronics, flexible electronics, mobile communications and low power sensor technologies. One of the main research challenges facing future developments in areas such as nanoelectronics, energy storage, and communications is the need to create devices which are more energy efficient. There is also a pressing need to develop devices which can harvest energy from their surroundings, which will be essential for the practical development of the “Internet of Things”.
To highlight some of the novel material and device research ongoing within the NMD group, a range of materials are currently investigated such as III-V semiconductors (e.g. InGaAs, InGaSb, GaSb) and two-dimensional semiconductor materials (e.g. MoS2, MoSe2 and WSe2). The study of high dielectric constant insulating oxides/semiconductor interfaces which will form the active regions of next generation logic devices is an area of particular interest for the NMD group. The group are also exploring the use of MOS systems for the generation of solar fuels through water splitting, and for the formation of copper metal diffusion barriers to low dielectric constant oxides for advanced metal interconnect applications.
For the metal gate MOS contacts, and for the metal-semiconductor source/drain contact regions, we are looking at new techniques to improve the contact resistance and ensure work function compatibility with the rest of the materials system. This activity spans all aspects of our research, since development and application of electrical characterisation methods relies heavily on ensuring as low as possible contact resistance and having a good understanding of the total resistance behaviour of materials.
Techniques employed are post-metal annealing to improve the metal/oxide and/or metal/semiconductor interface, pre-deposition surface treatments, activation annealing, metal bi-layers or alloys to improve interface and bulk chemistry, or interface control depositions.
Electrical characterisation methods used to understand the resistance behaviour of devices are Hall-effect measurements and the transfer length method (TLM) in order to understand the various contributions to the total measured resistance.
Project activities encompass funding from the European Commission, Science Foundation Ireland and industry partners.