Fabrication of free-standing nanoscale SiNx membranes with enhanced burst pressure via improved etching process

•Fabrication of uniform free-standing nanoscale SiNx membranes is presented.•Si substrate supporting the SiNx layer is wet-etched with KOH solution.•Small amount of surfactant added to KOH solution improves etching uniformity.•Membrane burst pressure is 4 times higher when prepared under optimized condition.