Adhesion effect of interface layers on pattern fabrication with GeSbTe as laser thermal lithography film

Adhesion of pattern structures is a very important issue in laser thermal lithography. In this paper, Si3N4 and ZnS-SiO2 were investigated as interface layers to improve patterns' adhesion to substrate on pattern fabrication with Ge2Sb2Te5 as laser thermal lithography film. Patterns were fabricated by laser direct irradiation with 650 nm and 405 nm laser writing systems (both NA = 0.9) and wet etching with 25 wt.% tetramethylammonium hydroxide solution. Experimental results showed that patterns were flaked off mostly and partly from the substrate in wet-etching process for samples without interface layer and with Si3N4 film as interface layer, respectively; but for samples with ZnS-SiO2 film as interface layer, regular and clear patterns were fabricated successfully under different fabrication conditions, and sub-wavelength line structures with width approaching to 390 nm were achieved by 405 nm laser system. The mechanism analysis implied that the matches of materials' thermal parameters might play important roles in the adhesion effect of interface layers on pattern fabrication. (C) 2012 Elsevier B.V. All rights reserved.