Low damage, highly anisotropic dry etching of SiC

摘要

A parametric study of the etching characteristics of 6H p(sup +) and n(sup +) SiC and thin film SiC(sub 0.5)N(sub 0.5) in Inductively Coupled Plasma NF(sub 3)/O(sub 2) and NF(sub 3)/Ar discharges has been performed. The etch rates in both chemistries increase monotonically with NF(sub 3) percentage and rf chuck power. The etch rates go through a maximum with increasing ICP source power, which is explained by a trade-off between the increasing ion flux and the decreasing ion energy. The anisotropy of the etched features is also a function of ion flux, ion energy and atomic fluorine neutral concentration. Indium-tin-oxide (ITO) masks display relatively good etch selectivity over SiC (maximum of (approximately) 70:1), while photoresist etches more rapidly than SiC. The surface roughness of SiC is essentially independent of plasma composition for NF3/O2 discharges, while extensive surface degradation occurs for SiCN under high NF(sub 3):O(sub 2) conditions.