Growth of 4H-SiC epilayers with low surface roughness and morphological defects density on 4° off-axis substrates

In situ etching and epitaxial growth have been performed on 4H-SiC 4° off-axis substrates with 100 mm diameter. In situ etching process optimizations lead to obtain step-bunching free epilayer surfaces with roughnesses of 0.2 nm and 0.8 nm, which were grown on the substrates with and without chemical mechanical polishing, respectively. Yet the epilayer surfaces free of step-bunching are more likely to suffer from various types of morphological defects than the ones with step-bunching. An increase in chlorine/silicon ratio during epitaxy can effectively suppress the appearance of defects on the step-bunching free epilayer surfaces. Using optimized epitaxial processes, we can obtain the total morphological defects density lower than 1 cm⁻² on 4H-SiC epilayers with surface roughness of 0.2 nm.

Highlights

► We presented the results on surface roughness and morphological defects of 4H-SiC epilayers on 4° off-axis substrates with 100 mm diameter.

► The impacts of the etch processes on the surface roughness of substrates and grown epilayers were shown.

► Smooth epilayer surfaces without step-bunching were obtained by optimizing etch processes.

► The increase in the Cl/Si ratio was demonstrated to effectively suppress the morphological defects on the epilayers with smooth surfaces.

► We can obtain the total morphological defects density lower than 1 cm−2 on 4H-SiC epilayers with roughness of 0.2 nm.

Source:Applied Surface Science

If you need more information about Growth of 4H-SiC epilayers with low surface roughness and morphological defects density on 4° off-axis substrates, please visit our website:http://www.qualitymaterial.net, send us email at powerwaymaterial@gmail.com.