Method of fabricating semiconductor device having multiple gate dielectric layers and semiconductor device fabricated thereby

A method of fabricating a semiconductor device having multiple gate dielectric layers and a semiconductor device fabricated thereby, in which the method includes forming an isolation layer defining first and second active regions in a semiconductor substrate. A passivation layer is formed on the substrate having the isolation layer. A first patterning process is carried out that etches the passivation layer on the first active region to form a first opening exposing the first active region, and a first dielectric layer is formed in the exposed first active region. A second patterning process is carried out, which etches the passivation layer on the second active region to form a second opening exposing the second active region, and a second dielectric layer is formed in the exposed second active region.