After forming a first-side epitaxial semiconductor region and a second-side epitaxial semiconductor region on recessed surfaces of a semiconductor portion that are not covered by a gate structure, at least one dielectric layer is formed to cover the first-side and the second-side epitaxial semiconductor regions and the gate structure. A second-side contact opening is formed within the at least one dielectric layer to expose an entirety of the second-side epitaxial semiconductor region. The exposed second-side epitaxial semiconductor region can be replaced by a new second-side epitaxial semiconductor region having a composition different from the first-side epitaxial semiconductor region or can be doped by additional dopants, thus creating an asymmetric first-side epitaxial semiconductor region and a second-side epitaxial semiconductor region. Each of the first-side epitaxial semiconductor region and the second-side epitaxial semiconducting region can function as either a source or a drain for a transistor.