Confinement-dependent wet etching kinetics in Si nanochannels

The wet etching of silicon (Si) is one of the most fundamental processes for the semiconductor industry. Although its etching kinetics on bulk Si surface have been thoroughly investigated, the kinetics of Si wet etching has yet to be fully addressed in nanoconfinements. Herein, we report the systematic study of potassium hydroxide (KOH) wet etching kinetics of amorphous-silicon(a-Si)-filled nanochannels. We discovered a nonlinear confinement dependence between the etching rate and the nanochannel dimension: the etching rate would increase with the increase in nanochannel height and then, gradually reaching a flat rate plateau. Our results provide new insights into the kinetic study of reactions in nanoconfinements and will shed light on etching process optimizations in industrial applications.