Mechanism of Corrosion Selectivity of NSb2Te Thin Films in the H3PO4/HNO3 Developer for Direct Laser Writing Nanolithography

The SbTe thin film is a promising heat-mode resist fordirect laserwriting nanolithography owing to the simple fabrication procedureand clear phase change thermal threshold. However, the lower corrosionselectivity and still unclear developing mechanism restrain the furtherdevelopment of SbTe thin films in the lithography fields. This workreports the NSb2Te thin film as a promising heat-mode resistwith a high corrosion selectivity of 500 in the H3PO4/HNO3 developer. Moreover, nanoscale structuresare successfully obtained with a linewidth of 150 nm and resolutionof 50 nm. The microstructural evolution and electrochemical corrosionbehavior of the NSb2Te thin film are investigated in detail,and the corrosion selectivity mechanism is further elucidated. Resultsreveal that the exposed NSb2Te thin film possesses Sb andTe hexagonal phases with a lower corrosion potential and charge transferresistance, which is readily oxidized and corroded in HNO3/H3PO4 solution. On the other hand, the as-depositedNSb(2)Te thin film will form N-Sb and N-Tebonds, possessing higher corrosion potential and charge transfer resistance.This results in the lower corrosion rate in HNO3/H3PO4 solution. Therefore, the giant difference ofmicrostructures and electrochemical behavior leads to the high corrosionselectivity of the NSb2Te thin film. The NSb2Te-based nanohole array is further fabricated to achieve tunableperfect absorption, and the maximum absorbance can reach 1.0 in thewavelength range of 400-800 nm. This work may provide a helpfulreference for the investigation of the direct laser writing nanolithographymechanism and nanoscale functional devices.