Site: IBM Zürich Research Laboratory
CH-8803 Rüschlikon, Switzerland
Tel: (41) 1-724 8111; Fax: (41) 1- 724 8964
Date Visited: 13 October 1997
WTEC: H. Goronkin (report author), M.C. Roco
The IBM laboratory in Rüschlikon employs approximately 200 people. The WTEC team visited the Science and Technology Department, formerly called the Physics Department. This department has about 50 people, of whom approximately 40 are scientists (including pre- and post-docs). In recent years, the lab's scope has evolved beyond mostly basic research to a problem-oriented mission in support of existing and alternative exploratory technologies that are on IBM's radar screen.
Heinrich Rohrer provided an introduction to the Science and Technology Department, pointing out the need for new ideas to move beyond the limits of present day technologies and devices.
The laboratories the WTEC team visited are well equipped and of a size normally found in universities. Many of the experimental apparatuses are set up by highly skilled technicians who also take an active part in the operation of the equipment for experimental purposes. Although the mission of the group is technology-driven, it is clear that science remains a key component and that the staff strives for understanding of the experimental results at the most basic level.
Collaborations with universities are numerous. The center leverages productivity considerably while fulfilling an educational purpose and creating a network of relationships of great value to all concerned. Some of these collaborations are supported by European (ESPRIT) and Swiss national programs.
Scanning probe technology was born in the IBM labs, and it has opened numerous areas for research in Switzerland. Scanning probes are used for atomic and molecular manipulation as well as characterization. Since the technique is relatively inexpensive, it is ubiquitous and drives many of the country's research projects.
Peter Vettiger described the IBM Zürich approach to mass storage using silicon microcantilevers with tips to record bits in a polymer medium (e.g., PMMA). Writing is achieved thermomechanically by heating the tip and creating an indentation in the softened polymer. Erasing is done in blocks rather than in individual bits by heating entire storage subfields.
Vettiger demonstrated a 5 x 5 array of individually accessible tips. In this case, the tips were fabricated using anisotropically etched silicon so that the 5 x 5 array used a 5 x 5 mm area (KOH etching provides sidewalls with a 54o slope). In order to increase the density of tips, a new etching process was developed that provides vertical sidewalls so that a 32 x 32 array can fit into a 1 x 1 mm area. Parallel operation of 1000 cantilever/tips is envisaged with x-y addressing achieved through multiplexing. Bits of 20-40 nm in size have been demonstrated. This extrapolates to more than 60 Gbit/in2 of data.
The array was demonstrated to image a test surface. In this demonstration, each tip provided an independent image.
James Gimzewski described the well-known buckyball abacus in which an STM tip is used to move C60 molecules along well-defined linear paths. He pointed out that the buckyball molecule can also be used as an amplifier when it is compressed by a scanning probe tip. He is generally working on concepts for manipulating and assembling molecules with the STM to implement useful functions.
R. Allenspach described the center's magnetism activities. This work focuses on the study of ultrathin magnetic films and multilayers with Cu/Co as a model system and has a direct impact on the understanding of magnetic properties such as giant magnetoresistance (GMR), exchange coupling, and surface anisotropy. It has led to the discovery of anisotropy oscillations due to quantum confinement in a Cu overlayer on a Co film. This work also includes detailed studies of film growth and morphology and how these correlate with magnetic properties.
Hans Biebuyck is a former student of George Whitesides at Harvard University, who is well known for microcontact printing using elastomeric stamps to transfer a pattern of self-assembling molecular layers to a substrate. The project he described encompasses both the science and pretechnology assessments of various high-resolution contact processing techniques like microcontact printing and microfluidic networks. The group has demonstrated the use of microfluidic networks for delivery of functionally distinct biomolecules onto targeted regions of a substrate and their application in localized biological assays. Stamps of very high quality and stability have been developed, and critical dimensions smaller than 50 nm have been achieved with microcontact printing.
Wanda Andreoni described the activities in computational materials science and the application of ab initio (Car-Parrinello) molecular dynamics techniques to various problems in science and technology, e.g., fullerenes, carbon nanotubes, and organic light-emitting structures for displays, catalysis, and chemical reactions. Some of this work is in direct support of ongoing local projects.