Although RMG technology is inherently more complex than gate-first integration, it has a number of advantages that allow increasing the device performance and that widen the choices in terms of high-k and metal gate materials. Testifying to its progress with RMG, imec presented a number of noted papers at the 2012 VLSI Technology Symposium (June 12-15, 2012, Honolulu, USA).
One of the current challenges to enable further device scaling is the choice of gate dielectric and gate electrode. For the selection of the gate electrode, the key parameters to consider are the work function, resistivity and compatibility with CMOS technology. Further scaling also requires continued improvement of the channel mobility, adding the options for improved stress management and also reliability control as a first-order consideration in the choice of materials and processes.
In the industry, the RMG approach is rapidly becoming the integration scheme of choice, and an alternative for the gate-first approach. In RMG, the high-k gate dielectric is deposited in the beginning of the flow or just prior to gate electrode deposition and the gate electrode is deposited after the formation of the junctions.
A clear advantage is the enhancement of the channel stress in shorter devices because of the dummy-gate removal, an intrinsic step in RMG flow. RMG also allows metal gate processes with a lower thermal-budget, which broadens the range of material options for work-function tuning and reliability control. Additional advantages are a lower gate resistance compared to gate-first, important for RF CMOS, and more room for mobility improvement.
Imec and its partners have had an important role in the introduction of high-k metal gate processes, building a strong expertise and track record. With the eye on further scaling to sub-20nm technology nodes, we are now evaluating RMG technology for different application, looking at different integration options, materials selection and engineering, and compatibility with advanced modules and device architectures, for which we collaborate with the major tool suppliers. For our partners, we conduct fair comparisons of options, and in-depth understanding of the physical mechanisms and techniques involved, and the chance to explore the limits in performance and reliability.
The research is performed in cooperation with imec’s key partners in its core CMOS programs Globalfoundries, INTEL, Micron, Panasonic, Samsung, TSMC, Elpida, SK hynix, Fujitsu and Sony.
Imec (imec.be) performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, US, China, India and Japan. Its staff of close to 2,000 people includes more than 600 industrial residents and guest researchers. In 2011, imec's revenue (P&L) was about 300 million euro.
Imec is a registered trademark for the activities of IMEC International (a legal entity set up under Belgian law as a "stichting van openbaar nut”), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland, part of Holst Centre which is supported by the Dutch Government), imec Taiwan (IMEC Taiwan Co.) and imec China (IMEC Microelectronics (Shanghai) Co. Ltd.) and imec India (Imec India Private Limited).