In one aspect, a method of forming a semiconducting device can comprise forming, on a substrate surface, a stack comprising semiconductor material sheets and a bottom semiconductor nanosheet; forming a trench through the stack vertically down through the bottom semiconductor nanosheet, thereby separating the stack into two substacks; selectively removing the bottom semiconductor nanosheet, thereby forming a bottom space extending under the substacks; and filling the bottom space and the trench with a dielectric material to provide a bottom isolation and formation of a dielectric wall between the substacks.