Electrically trimmable resistors have been manufactured using the phase change alloy Ge 2 Sb 2 Te 5 . High resistivity values (about 1 mΩ cm) and almost zero temperature coefficient of resistance (TCR) have been obtained using resistors with hcp phase of metallic behavior and converting a small region of the film into the fcc phase, with opposite trend of resistance versus temperature. The conversion into the fcc phase has been obtained through two electric pulses, the first for melting and quenching in the amorphous phase and the second for crystallization in the fcc semiconductive phase. Theoretical considerations together with the experimental measurements allow to determine the proper ratio between the metallic and the semiconductive phase required to obtain a target resistance and temperature dependence. For example, a resistor almost independent on the temperature can be achieved by electrical …