Combined Application of Section and Projection Topography to Defect Analysis in PVT-Grown 4H-SiC
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Combined Application of Section and Projection Topography to Defect Analysis in PVTGrown 4H-SiC H. Wang1, F. Wu1, S. Byrappa1, S. Shun 1, B. Raghothamachar1, M. Dudley1, a, E. K. Sanchez2, b, G. Chung2, D. Hansen 2, S. G. Mueller2, and M. J. Loboda2, 1 Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY, USA 11794-2275 2 Dow Corning Compound Semiconductor Solutions, Midland, Michigan, USA 48686-0994 a [email protected], [email protected] ABSTRACT The combined application of section and projection topography carried out using synchrotron white beam radiation can be a powerful tool for the determination of the three-dimensional configurations of defects in single crystals. In this paper, we present examples of the application of this combination of techniques to the analysis of defect configurations in PVT-grown 4H-SiC wafers cut perpendicular and parallel to the growth axis. Detailed correlation between section and projection topography of threading screw dislocations (TSDs) is presented with particular emphasis being laid on the determination of the signs of the dislocations. Further, information can also be determined regarding the position of the dislocations within the crystal depth. In addition, similar correlation is presented for threading edge dislocations (TEDs) and basal plane dislocations (BPDs). The section topography images of dislocations can comprise direct, intermediary and dynamical contrast and all three types are observed. The application to the study of stacking faults will be also discussed in detail. INTRODUCTION 4H-Silicon Carbide (SiC) is a widely used semiconductor for high power devices due to its outstanding properties such as higher thermal conductivity, higher breakdown voltage and high saturated electron drift velocity [1]. However, the detrimental effects of defects, e.g., dislocations and stacking faults, inside these crystals requires crystal growth scientists to gain knowledge of the formation mechanisms and behavior of the defects to develop strategies in order to lower the densities of these defects [2-3]. X-ray projection topography is a widely used non-destructive technique to characterize defects in the crystals but provides limited depth sensitivity and sensitivity to orientation contrast. In this paper, in order to address these limitations, projection and section topography are combined together to reveal the three-dimensional configuration of defects. Section topography of dislocations includes three types of image comprising direct, dynamic and intermediary contrast. Under low absorption conditions (μt
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