A new structure of nanopore chip for solid state nanopore sequencing technology based on kinetic profreading is designed

in addition to sandwich structure layers of Si3 N4/Si O2/Si3 N4

increase the double sacrifice layers of Si O2/Si3 N4

while reducing the stress of each layer free-standing film

it can also reduce the noise by increasing capacitance

the thickness of each layer films is determined by thermal stress computation to avoid cracking of each layer film during the production process. Process for fabrication of sandwich structure film is designed using nano-electro-mechanical systems（ NEMS）

including low-pressure chemical vapor deposition（ LPCVD）

lithography

reactive ion beam etching（ RIE） and wet etching and so on

to gain high quality free-standing sandwich structure film. The film fabrication is further etched by focused ion beam（ FIB）

a nanopore of about 5 nm in diameter is made with Zeiss’ s helium ion microscope.