Stretchable and transparent thermally-grown silicon dioxide film for encapsulation

Abstract

Thermally grown silicon dioxide film is an important material in integrated circuits (ICs) as gate oxides, doping barrier, surface passivation, etc. as thermal oxidation grows high quality silicon dioxide film showing excellent electrical insulator resistivity, passivation ability to prevent diffusion of dopants, etc. As it has limitations of the substrate, Si, applications for thermally grown silicon is limited. In this research, we studied thermally grown SiO2 film as an encapsulation film by using its ultra-low water permeability as we expected thermally grown silicon dioxide film to have ultra-low water permeability and high elasticity due to its rare defects, high density and high uniformity. And we increased stretchability of thermally grown silicon dioxide film with two ways, using thickness effect and applying wrinkled structure. To increase the stretchability, first, the thickness of thermally grown SiO2 films were decreased less than 200 nm to observe thickness effect. Tensile tests were performed on those films and the results showed that thinner film has higher elastic limit than thicker film has. Second, wrinkled structures were applied on thermally grown SiO2 film by using prestrained elastomer and the wrinkled SiO2 film having 5% of stretchability was fabricated. The influence of thickness on mechanical properties of thermally grown SiO2 film and mechanical behavior of wrinkled SiO2 film during the fabrication and while stretching will be discussed.