<p>There is provided a technique that can increase the speed of a setting operation, which determines the speed of a write operation in a semiconductor device including memory cells using a phase-change material. The technique uses a means for causing a solid-phase growth without melting the phase-change material. A set pulse voltage is applied to the phase-change material in two stages: the first-stage voltage sets the temperature of the phase-change material to a temperature at which the fastest nucleation is obtained; and the second-stage voltage sets it to a temperature at which the fastest crystal growth is obtained. Moreover, the technique uses a means for controlling the two- stage pulse voltages applied to the phase-change material by the two-stage voltages applied to a word line capable of reducing the drain current variation.</p>
