Workshop Overview

Objectives:

To review recent progress on the "atomic-scale" physical, chemical and electrical understanding of ultrathin dielectrics on silicon-based materials, to identify priority directions for future basic research in the field, and to promote intensive interdisciplinary scientific exchange and working contacts between leading researchers in the field.

Type of Workshop: ARW with ~50 participants

Workshop Overview

The main goal of this ARW is to examine at the nano and atomic scale the very complex scientific issues which pertain to the use of ultrathin dielectrics in next generation Si-based semiconductor devices. The semiconductor industry continues to develop at a phenomenal pace. To the surprise of many, SiO₂/Si-based MOSFET's have been scaled well beyond what was earlier imagined, and have remained at the core of most semiconductor logic and memory devices that are currently produced. Semiconductor manufacturing industry must reach or exceed the capability to economically produce 16GB DRAM technology within 10-12 years. An extrapolation of current scaling trends indicates that minimum feature sizes below 0.1µ and gate oxide thicknesses of approximately 3.5nm (just a few atomic layers!) will be required. Given the absence of a feasible alternative on the near horizon, well-focused basic scientific research and aggressive development programs on the silicon oxide and oxynitride on silicon systems must continue, especially on the ultrathin 1-5nm scale, as pointed out by the Semiconductor Research Corporation and many other groups. Despite a long history of research, many open questions remain. Two other Si-based materials (SiC and SiGe) have also generated much excitement recently in the community; the growth of dielectrics on these substrates also deserves serious basic scientific study.

To progress towards overcoming the many fundamental obstacles blocking scaling of ultrathin SiO₂-based dielectrics and to improve our basic knowledge of oxynitrides, we have formulated a workshop with the main goal being to develop an atomic-scale understanding of the complex set of electrical, structural, compositional and processing issues that pertain to ultrathin dielectrics (mostly SiO₂ and SiO_xN_y) on silicon based (Si, SiC and SiGe) substrates. We propose a one week advanced research workshop (ARW) in which both NATO country and CP-based leading researchers on ultrathin dielectrics meet, tutor each other about both their recent results and thinking, and perhaps come to some consensus as to where research and development should be directed over the next five years. The list of researchers represents a rather diverse group of scientists and engineers who bring a broad array of backgrounds and strengths into the workshop. The group comes from academic, industrial and governmental labs, and has both experimental and theoretical researchers with backgrounds in basic and applied areas of physics, chemistry, electrical engineering, surface science, and materials science. In the problems surrounding next-generation ultrathin dielectrics it is necessary for theoretical quantum chemists to speak with processing engineers, and device engineers and modellers to listen to surface physicists. The problems are complex and demand a broad vision.

We have planned the meeting thematically. Following a few introductory presentations, the first day will concentrate on recent advances in experimental studies for pure SiO2/Si analysis (detection, profiling, etc.) and related theoretical work. A thorough knowledge of the pure SiO2/Si system is required before the more complex multicomponent systems can hope to understood or optimized. Unfortunately, even this most "simple" system remains at the base of some controversies that now pervade the literature. This first day (and some of what follows later in the week) will focus on the atomic scale mechanisms of ultrathin oxide growth, the oxide and interface microstructure, and a cross-correlation of experimental tools and theoretical models of analysis. The second day will be dedicated to the scientific and technical challenges surrounding the use of oxynitrides as a dielectric film. Atomic level understanding of nitrogen incorporation and nitrogen function will be discussed, as well as controlled oxynitride layering methods. On the third day we will discuss the surface science limit of structure, adsorption, and reactivity during initial dielectric growth on Si-based substrates and ultra cleaning technologies. In the evening we will review several key issues pertaining to the science and technology of ultrathin dielectric film growth. On the fourth day the current critical concerns on device electrical characterization, tunneling and defect structure will be presented and discussed. In the afternoon, the important and poorly understood issues pertaining to water and H/D presence, and their role and use in dielectrics will be covered. On the fifth day advances in dielectric growth on new compound SiC and SiGe substrates will be presented; to date very little basic scientific literature exists concerning dielectric growth or deposition on these very important new materials. In the afternoon, a review and open discussion will be held to focus both individual and collective plans for future research on ultrathin film dielectrics.