Fig. 2.

Tuning pore diameter in ITE SiN membranes by etching time. SEM images and radius distributions of membranes with conical pores, which were obtained by etching irradiated SiN films in H₃PO₄ for 20 min (A) and 50 min (B). The images show the large opening of the conical pores; the small opening could not be resolved with SEM for low etching times. (C) Pore radius distributions at different etching times. (D) Mean of the pore size distribution shown in C as a function of etching time; the red line presents plot of Eq. 1 for g = 1.3 nm/min.