HREM Analysis of SiC Grain Boundary Structure

Abstract

A grain boundary of high purity SiC bicrystal grown by sublimation recrystallization method was observed by high resolution electron microscope in order to analyze the most stable, or the most basic, structure of SiC grain boundary. The boundary was expected to realize the most stable structure because it was grown slowly without any applied external forces which may prevent from free formation of the boundary. Purity of the crystal was kept below 10^-17/cm³ in donor concentration. Observed structure of the boundary was coincided with one of three models which were constructed so that the number of dangling bond was least throughout the possible atomic arrangement at that orientation relationship. The reason why only one structure was preferred among three in spite of that the number of dangling bond was same was attributed to the effect of ionic bonding component of SiC crystal.