Effect of etching solution concentration on preparation of Si holes by metal-assisted chemical etching

Abstract The effect of the etching solution concentration on profile vertical microscale holes formed a Si(100) substrate by metal-assisted chemical (MacEtch) was investigated. MacEtch performed at different ratios (characterized their molar ratio ρ = [ HF stretchy="false">] / close="]" open="[" + mathvariant="normal">H 2 mathvariant="normal">O ), and Au catalyst split above certain ratio. Au–Si interface in samples after observed using transmission electron microscopy, which revealed that there porous SiO x interlayer between Si, layer became thinner as increased. almost disappeared under conditions when split. We propose two hypotheses for mechanism catalytic fracture during MacEtch: due to Si atoms diffusing into grain boundaries polycrystalline interdiffusion, mechanical stress caused heterogeneous etching.