We propose a simple and cost-effect method, current-stimulus dielectric breakdown, to
manipulate the 3D shapes of the nanochannels in 20-nm-thick SiNx membranes. Besides
the precise control of nanopore size, the cone orientation can be determined by the pulse
polarity. The cone angle of nanopores can be systematically tuned by simply changing the
stimulus pulse waveform, allowing the gradual shape control from conical to obconical. After
they are formed, the cone angle of these nanopores can be further tuned in a certain range …