A microelectromechanical (MEMS) device has a movable member supported above a substrate on a via support. The member and via support are fabricated integrally from first and second member forming layers. A first member forming layer forms a lower part of the member and supporting structure for the via support. First and second fill layers are deposited and patterned to form a plug that fills an inner cavity opening in the via structure. The plug is planarized to a planar part of the first member forming layer, and a second member forming layer is deposited over the first member forming layer and the planarized plug to form an upper part of the member. The via support may have a cavity filled by BARC layers.