Radiofrequency (RF) skin treatment devices and methods are provided herein. RF energy is delivered via electrodes in a phase-controlled manner which heats skin volumes below the surface more than the skin surface itself. At least one electrode at least partially encloses at least one other electrode. The combination of controlling the phases of the RF energy delivered to different electrodes and the enclosing configuration of the electrodes allows concentrating the delivered energy in specific regions below the skin surface at a particularly high efficiency. Configurations of the enclosing and the enclosed electrodes, their forms and combinations with other electrodes and the phase polarities applied to the electrodes are also provided.