THRESHOLD SWITCHING IN TE46-XAS32+XGE10SI12 CHALCOGENIDE GLASS SYSTEM

Five different compositions of Te46-xAs32+xGe10Si12 chalcogenide glass system were prepared with the atomic percentages 0, 1, 2, 4 and 5. I- V characteristic curves for thin film samples of the investigated comp ositions were typical for threshold switching behaviour. It was found that the threshold voltage increased linearly with film thickness in t he investigated range (100-800 nm) for all compositions. However, thre shold voltage V-th decreased exponentially with temperature. The thres hold voltage activation energy (epsilon) was obtained for the investig ated compositions. The electrical conduction activation energy (E(sigm a)) for the investigated compositions was obtained from the correspond ing temperature dependence of film sample resistance. The ratio (epsil on/E(sigma)) was obtained theoretically on the basis of an electrother mal breakdown process. A good agreement was obtained between theoretic al and experimental values of (epsilon/E(sigma)). The lifetime for thr eshold switch devices on the basis of the investigated compositions wa s measured also. The compositional dependence of V-th, epsilon and the lifetime was also investigated. (C) 1997 Elsevier Science Ltd. All ri ghts reserved.