A handset is disclosed which comprises a display 3 and a scroll key 9 for scrolling data on the display. The superjunction structure has alternately arranged n-type regions and p-type semiconductor regions layered parallel with the drift direction of carriers, permitting current flow when turned ON and depleting when turned OFF. Because the dielectric material is deposited after high temperature processing of the device, there is negligible diffusion of germanium into the dielectric material. During operation the axial fan conveys operating air in the direction of the axis of rotation of the axial fan through a blower tube disposed downstream of the axial fan.