Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Tham khảo tài liệu 'silicon carbide materials processing and applications in electronic devices part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 200 Silicon Carbide - Materials Processing and Applications in Electronic Devices Fig. 10. Pores and micropipes at the boundary of 6H-SÌC inclusion in 4H-SÌC wafer. a SR phase-contrast image. b PL image. c The sketch outlines the inclusion and the pores as indicated by the black and white arrows respectively. The number 1 points to a slit pore and the numbers 2-5 to tubular pores. the edge of the left concave inclusion as defined in Fig. 11 c . The pores spread over the inclusion boundary and propagate deeply inside the wafer. The phase-contrast image Fig. 4 b also reveals that the pores are produced through the coalescence of micropipes. The observed micropipes remarkably deviate from the growth direction which we attribute to the interaction of micropipes with the polytype inclusion. Mapping with a lower magnification revealed a significant reduction in micropipe density nearby to the pores which can be explained by the absorption of micropipes by the pores. The following scenario for pore growth is suggested as is illustrated by the sketch in Fig. 12. At the beginning a few neighboring micropipes are attracted to an inclusion with no pore to accommodate the orientation mismatch between the inclusion and the matrix crystalline lattices Fig. 12 a Gutkin et al. 2006 2009b . This orientation mismatch is described mathematically through the components of the inclusion plastic distortions Gutkin et al. 2006 . In the case of two nonvanishing plastic distortion components micropipes are attracted to a corner of the inclusion Figs. 12 a and 12 b where they have an equilibrium position Gutkin et al. 2006 2009b . Let the first micropipe occupy its equilibrium position at this corner Fig. 12 b . Then another micropipe containing a dislocation of the same sign as the first micropipe is attracted by the inclusion to the same equilibrium position. If the inclusion is powerful enough that is the plastic distortions are large the attraction force exerted by Fig. 11. .
