The invention relates to a semiconductor device, a manufacturing method and an electronic device. The method comprises steps: a semiconductor substrate is provided, multiple layers of laminated structures are formed on the semiconductor substrate, and the laminated structure in each layer comprises a bottom electrode layer and an isolation layer which are laminated sequentially; the laminated structure is patterned to the semiconductor substrate to form a plurality of grooves and laminated structure units isolated through the grooves in the laminated structure; an insulating layer and a sacrificial layer are formed on the side wall of the laminated structure unit and the bottom part of the groove; the sacrificial layer is patterned to form a plurality of mutually-spaced parts in the extending part of the laminated structure unit; and a top electrode layer is formed on the sacrificial layer to cover the sacrificial layer. Through the method of the invention, the contour performance of the groove can be improved, the performance of a 3D RRAM is improved, and the functional losses are reduced.