A method and related structure provide a void-free dielectric over trench isolation region in an FDSOI substrate. The structure may include a first transistor including a first active gate over the substrate, a second transistor including a second active gate over the substrate, a first liner extending over the first transistor, and a second, different liner extending over the second transistor. A trench isolation region electrically isolates the first transistor from the second transistor. The trench isolation region includes a trench isolation extending into the FDSOI substrate and an inactive gate over the trench isolation. A dielectric extends over the inactive gate and in direct contact with an upper surface of the trench isolation region. The dielectric is void-free, and the liners do not extend over the trench isolation.