Simple fabrication of microfluidic channel with nanoporous membrane formed by conventional physical vapor deposition

In this paper, we first proposed that the thin film deposited by conventional physical vapor deposition can be used as a membrane for molecular filtration because of its columnar grains. The columnar grains of thin membrane were formed naturally during physical vapor deposition and offered nano-sized pores to filter molecules. A microfluidic channel integrated with the membrane was successfully fabricated, and the existence of the nanopores was proved by etching sacrificial layer under the columnar thin film. Thickness of fabricated membrane is 300nm, and the diameter of the pores in the membrane is estimated below about 10nm.