Nano-holes for vacuum applications

6th Vacuum and Surface Sciences Conference of Asia and Australia

Ierardi, V.^1 ; Firpo, G.^1 ; Valbusa, U.^1

NanoMed Labs, Physics Department (DIFI), University of Genova, Largo R. Benzi 10, 16146 Genova, Italy^1

关键词: Detection instruments;    Fabrication and characterizations;    Molecular flow;    Silicon nitride membrane;    Temperature data;    Temperature fluctuation;    Three dimensional images;    Very high resolution;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/439/1/012033/pdf
DOI  :  10.1088/1742-6596/439/1/012033

来源: IOP

【 摘 要 】

In order to calibrate leak-detection instruments, devices based on permeation leaks and physical leaks are used. Unfortunately, permeation leaks are very sensitive to small temperature fluctuations and can be used only with those gases for which permeating materials are available. While, physical-leaks that overcome these restrictions are susceptible to clog, in particular when the gas flow through them is in viscous regime. Furthermore, for many type of leak devices, the conductance is not predictable based on dimensional, gas species and temperature data, for this reason no estimates or only rough estimates of leak rates are possible for conditions under use where they differ from those of the calibration. Here, we present the fabrication and characterization of a new kind of physical-leak devices based on nano-holes, which overcome these problems. Nano-holes, with diameters less than or equal to 200 nm, work in molecular-flow regime up to atmospheric pressure and for this reason they do not clog. The nano-holes are manufactured by milling a silicon nitride membrane by means of Focused Ion Beam (FIB), and their shapes are characterized by both Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Because of the capability of the AFM to acquire surface three-dimensional images with very high resolution, it is a very useful tool to perform a topographic characterization of the nano-holes.