A thermophonic investigation of switching and memory phenomena in thick amorphous chalcogenide films

We have employed a thermophonic technique [1] supplemented by numerical analysis in order to study switching and memory effects in the memory-type alloy Ge15 Te18 S2 [2]. The study was initiated because: 1) there was still some doubt as to whether the mechanisms for the initiation of the switching event from a high resistance OFF-state to a low resistance ON-state is predominantly electronic [3-10] or thermal [11-14]; 2) the technique provides a novel way of studying the various phenomena [15] and, for the first time, determining the temperature-time profile during the three phases of the switching cycle.