Nano-holes as standard leak elements

• Published in: Measurement : journal of the International Measurement Confederation 2014-12, Vol.58, p.335-341
• Main Authors: Ierardi, Vincenzo, Becker, Ute, Pantazis, Sarantis, Firpo, Giuseppe, Valbusa, Ugo, Jousten, Karl
• Format: Article
• Language: English
• Subjects: AFM; DSMC; Focused ion beam; Gas flow meter; Leak rate measurement; Nanotechnology; SEM; Si3N4; Standard leak; STEM; Vacuum metrology
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2014.09.017

•Nanoholes exhibit molecular flow in pressure range from high vacuum up to 100kPa.•Nanoholes can be used as predictable leak for any non-condensable gas species.•The geometrical dimensions were determined by SEM, STEM and AFM techniques.•Nanoholes conductances were calculated by DSMC method from the measured dimensions.•Calculated and measured conductance agreed within their respective uncertainties. Short tubes with diameters of the order of 200nm were drilled into silicon nitride (Si3N4) membranes of 200nm thickness by focused ion beam technology and examined as leak elements for vacuum technology applications. These nano-holes exhibit molecular flow in the pressure range from high vacuum up to 10kPa and can therefore be used as predictable leak elements for any non-condensable gas species. The geometrical dimensions were determined by SEM, STEM and AFM techniques. By Direct Simulation Monte Carlo method the conductances of these short tubes were calculated from the measured dimensions. The calculated conductance agreed with the value measured by comparison with a primary gas flowmeter within their respective uncertainties.