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, Si"3N"4 and ZnS-SiO"2 were investigated as interface layers to improve patterns' adhesion to substrate on pattern fabrication with Ge"2Sb"2Te"5 as laser thermal lithography film. Patterns were fabricated by laser direct irradiation with 650nm and 405nm laser writing systems (both NA=0.9) and wet etching with 25wt.% 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 Si"3N"4 film as interface layer, respectively; but for samples with ZnS-SiO"2 film as interface layer, regular and clear patterns were fabricated successfully under different fabrication conditions, and sub-wavelength line structures with width approaching to 390nm were achieved by 405nm 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.