A microelectronic device including a microelectronic circuit and at least one planar flexible lead. These planar flexible leads are adapted to bend and flex during mechanical stress, allowing direct mounting of the device to a member and able withstand extreme thermal cycling between −20° C. to +80° C. encountered in terrestrial applications. Advantageously, the microelectronic device is adapted to be both weldable and solderable. The invention may comprise a solar cell diode, which is flexible and so thin that it can be affixed directly to the solar panel proximate the solar cell.