Leuven, Belgium --- December 10, 2003 ---  IMEC, Europe’s largest independent microelectronics and nanotechnology research center, announces that they have successfully demonstrated the use of high-k dielectrics and metal gates to values below one nanometer. Achieving this level of electrical performance using materials other than the traditional polysilicon-based counterparts removes one of the industry’s so-called ‘red brick wall’ barriers to advancing semiconductor technology. 

As part of its industrial affiliation program, an IMEC research team utilized metal gates to overcome the problems imposed by the interaction between high-k materials with the commonly used polysilicon electrode.

“These results show that tremendous progress  -- especially in terms of transistor drive current performance and threshold-voltage stability  -- has brought the concept of high-k metal-gate devices for both high-performance applications and low standby power close to real implementation,” said Dr. Luc Van den hove, Vice President Silicon Process and Device Technology at IMEC.  “We are convinced that within our industrial affiliation program we now have all the necessary technology and understanding to bring high-k metal-gate devices to implementation in the next technology nodes and within ITRS timeline specifications.”

Using TiN or TaN gates and HfO2 as dielectric, aggressive scaling down to an 0.8nm equivalent-oxide thickness (EOT) was demonstrated in both nMOS (8.2Å EOT) and pMOS (7.5Å EOT) transistors. The metal-gated devices outperformed their polysilicon-based counterparts in terms of electrical performance parameters, including high conductance, low leakage and reduced threshold-voltage instabilities.  Besides the elimination of gate depletion, the metal gates enhanced high-k scalability and significantly reduced gate-leakage by up to three orders of magnitude. Transistor drive current also improved significantly.

To realize sub-1nm EOT scaling, appropriate interfacial oxide control both prior to and during high-k deposition was applied. The lowest EOT values were typically obtained using a ‘minimal interface approach’ (i.e. minimal EOT contribution).  In order to achieve this, scaled chemical oxide interfaces with controlled thickness and precisely controlled deposition and annealing conditions were used. HfO2 was deposited by atomic layer chemical vapor deposition (ALCVD™).

Excellent nMOS performance was demonstrated with performance indicators slightly exceeding those for poly/SiO2-based devices and significant improvement of the pMOS performance since the hole mobility remained constant down to the lowest EOT values. In addition, not only the initial performance but also the threshold-voltage instabilities due to trapping were strongly reduced as compared to typical results on high-k films with polysilicon electrodes.

Part of this research has been done in collaboration with IMEC’s high-k industrial affiliation program partners, namely International Sematech and its member companies, Renesas, Matsushita and Samsung.

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Notes to editors

About IMEC

IMEC (Inter-university MicroElectronics Center) was founded in 1984 and today is Europe’s largest independent research center in the field of microelectronics, nanotechnology, enabling design methods and technologies for ICT systems. IMEC's activities concentrate on the design technology for integrated information and communication systems; silicon process steps and modules, silicon processes; nanotechnology, microsystems, alternative devices, packaging; solar cells; and training in microelectronics. IMEC is headquartered in Leuven, Belgium, and has a staff of more than 1300 people including over 380 industrial residents and guest researchers. Its revenue in 2002 of more than 138Meuro was derived from agreements and contracts with the Flemish government, equipment and material suppliers and semiconductor and system-oriented companies worldwide, the EC, MEDEA+ and ESA. News from IMEC is located at www.imec.be.

For more information:

Katrien Marent

Corporate Communication Manager

IMEC, Kapeldreef 75

B- 3001 Leuven, Belgium

Tel +32 16 28 18 80 Fax +32 16 28 16 37

Email: Katrien.Marent@imec.be