“The paper deals with certain aspects of degradation of silicon carbide bipolar devices.”

The primary reason is: It was timely. The paper deals with certain aspects of degradation of silicon carbide-based bipolar devices. The degradation problem was first announced by the ABB group at the European Conference on Silicon Carbide and Related Materials in the fall of 2000 and, at the time, it appeared to threaten all potential silicon carbide applications in high voltage switching devices. Naturally, the problem attracted a lot of attention. Our publication a year and a half later focused not only on the structure of defects responsible for the degradation but also, and more importantly, pointed to specific mechanisms involved in this process. In a way, the paper pointed out a possible route of eliminating the degradation effects. It is this "forward looking" aspect of our contribution made early in the process that made the paper valuable to others.

It identified a specific mechanism responsible for the degradation of SiC devices.

The primary motivation for the development of silicon carbide as a new semiconductor is the potential application in powerful electronic devices, i.e., devices that control large currents and high voltages. Current and future applications include highly efficient power supplies in computers, electric vehicles, and electric power distribution systems. Performance of such devices degraded with time and this phenomenon needed to be eliminated before the devices could be commercialized. The paper was an early contribution toward this goal. We, as members of the SiC community, were apparently successful. Prototypes of the first bipolar SiC power devices are likely to enter into production within the next two years.

My group was working on defect analysis in SiC crystals using electron microscopy as a tool for number of years. The difficulty lies in the very low defect densities in this material and the very small volume of the TEM sample. In traditionally prepared samples, one does not see any defects at all. The techniques which we have developed turned out to be well-suited for an analysis of SiC devices and the group at the ABB Corporate Research Laboratory in Kista, Sweden approached us with a proposal to work jointly on the degradation problem. This paper is the result of this collaboration. Staying up late at night to drink beer and talk shop at conferences was an essential part of starting the interaction.