Etching of 4H-SiC using a NF3 inductively coupled plasma

Etching of silicon carbide (SiC) was conducted in a NF3/CH4 inductively coupled plasma (ICP) at low pressure. The etch responses examined include the etch rate, surface roughness, and profile angle. For the variations in the source power, the direct-current (DC) bias strongly affected the etch rate. The profile angle varied inconsistently with the bias power. It was commonly observed without regard to the pressure level that, at lower gas ratios, the surface roughness was inversely related to the DC bias. At higher gas ratios, the surface roughness seemed to be dominated by surface reactions. In estimating etch mechanisms, the DC bias played an important role in qualitatively separating chemical and physical effects.