IDENTIFICATION OF AMORPHOUS ZONES IN THE GETESB SYSTEM

We studied the phase diagram of the Ge-Te-Sb ternary system in order to establish the different compositions which lead to an amorphous material. The system was investigated by differential thermal analysis, differential scanning calorimetry and by X-ray diffraction at fixed temperature. We have determined the eutectic compositions of the system and tested the ability of these compositions to give an amorphous material. Only a small range of compositions, around the Ge15Te82Sb3 eutectic compound, gives an amorphous material after quenching from the melt; this range of composition is widened when a vapour deposition technique is used. One of these compositions has two glass transition temperatures and two crystallization peaks, showing the existence of two amorphous states in the sample.