Preface: phys. stat. sol. (b) 245/7
Authors: Ley Lothar , Pensl Gerhard 
Published: June 2008

This special issue of physica status solidi contains 18 invited topical reviews which are meant to represent key aspects of our current understanding of the material and physical basis of silicon carbide (SiC) as an emerging material for applications in semiconductor devices. The majority (ten out of eighteen) of the contributions are from members of the Research Unit (Forschergruppe 476) “Silicon carbide as semiconductor material: novel aspects of crystal growth and doping” which was funded by the Deutsche Forschungsgemeinschaft (DFG) from 2002 to 2008. The members of the research unit came from various disciplines in physics and engineering at the University of Erlangen‐Nürnberg. The Research Unit not only benefitted from a preceding Collaborative Research Center (Sonderforschungsbereich) at the same university that was for 9 years also involved in basic research on SiC and comprised some of the same members; the Research Unit was also embedded in and collaborated intensely with strong commercial enterprises active in SiC crystal growth (SiCrystal) and SiC‐based semiconductor device development (SiCEd) in and around Erlangen. Naturally, such a long and intense involvement in SiC‐related research fosters outside collaborations as well. In fact, over the years, we were fortunate enough to be able to cooperate with the leading scientists in the field of SiC research worldwide. Hence we thought it appropriate to ask some of these collaborators to contribute to the current volume and most of them were kind enough to do so. As a consequence, eight contributions are supplied by scientists from outside the Research Unit thereby widening the scope of this volume considerably.

The topics covered are grouped in five subsections and the volume is aptly introduced by two contributions from industry. Kimimori Hamada from Toyota Motor Corporation gives us a vision of SiC‐based electronics in the hybrid‐driven automobile of the future. Whereas Friedrichs from SiCEd details the design challenges and opportunities that SiC‐based electronics face vis‐à‐vis its closest competitor silicon.

In the section entitled “Crystal Growth” methods and results for epitaxial and bulk growth of hexagonal SiC are reviewed in the two articles by Epelbaum et al. and by Sakwe et al. A novel way to grow low defect cubic 3C‐SiC for high performance vertical MOSFETs is presented by Nagasawa et al. in the same section.

The largest group of articles, compiled in the next section, covers various aspects of defects in SiC. Identification of intrinsic defects by spin resonance methods is the topic of the article by Isoya et al. Camassel and Juillaguet as well as Hundhausen et al. cover optical techniques employed to characterize defects in SiC. The electrical and topological properties of 4H‐SiC after Al implantation for doping are reviewed by Rambach et al. while Kimoto et al. describe means to control the concentration of lifetime‐killing defects in 4H‐SiC epilayers. Overall, this important aspect of SiC research is greatly aided by modern, density‐functional‐type total energy calculations as exemplified in the contribution by Bockstedte et al. which opens the section on defects.

In the section on processing two papers by Krieger et al. and by Pensl et al. deal with a topic of crucial importance for MOSFET devices, namely interface traps and means for their reduction. The article by Reshanov et al. in the same section reports on the beneficial effects of graphitic interface phases for metal/SiC contacts.

The volume closes with papers on non‐semiconducting aspects of SiC which are gathered in a section entitled “Novel Trends”. The use of SiC as MEMS material in thermally and chemically demanding applications is reviewed by Zorman et al. and Ke et al. describe fundamental studies of the electrochemical etching of nanoscale columnar structures in 6H‐SiC which are promising for a variety of future applications of SiC. A novel aspect of considerable attraction that emerged only in the last couple of years is the epitaxial growth of graphene on SiC. This topic is treated both from an experimental as well as a theoretical point of view in the contributions by Seyller et al. and Mattausch and Pankratov, respectively.

We are indebted to all authors for their effort and time; it is their excellent insight and meticulous work that renders this volume a timely snapshot of the current status of SiC research worldwide. We are particularly grateful to the considerable number of anonymous reviewers who took great pains to review and thereby improve the manuscripts. We thank the editorial staff of physica status solidi for their unwavering and good humoured support during the production of this special issue. Last but not least, the funding of the Research Unit in Erlangen over the course of six years through the Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged.

June 2008