Step bunching fabrication constraints in silicon carbide

Experimental evidence is given for a newly observed surface morphological phenomenon (step bunch bleed) and its implications for device fabrication constraints in ion implanted 4H-silicon carbide (4H-SiC) are discussed. Step bunch bleed is the result of surface step bunching spreading during a high-temperature anneal process to bridge closely adjacent patterned lithographic features where step bunching would otherwise not occur. It is found that the phenomenon of step bunch bleed could limit the minimum practical lithographic distance between adjacent nitrogen implants within a boron well structure in 4H-SiC to the order of 1 μm—depending on the crystallographic orientation of the implant pattern.