Memory switching of germanium tellurium amorphous semiconductor

The dc conductivity and switching properties of amorphous GeTe thin film of thickness 262 nm are investigated in the temperature range 303-373 K. The activation energy Delta E sigma, the room temperature electrical conductivity sigma(RT) and the pre-exponential factor sigma(0) were measured and validated for the tested sample. The conduction activation energy Delta E-sigma, is calculated. The I-V characteristic curves of the thin film samples showing a memory switching at the turnover point (TOP) from high resistance state (OFF state) to the negative differential resistance state (NDRS) (ON state). It is found that the mean values of the threshold electrical field E-th decreased exponentially with increasing temperatures in the investigated range. The switching activation energy Delta E-th is calculated. Measurements of the dissipated threshold power P-th and the threshold resistance R-th were carried out at TOP point at different temperatures of the samples. The activation energies Delta E-R and Delta E-p caused by resistance and power respectively are deduced. The results obtained support thermal model for initiating switching process in this system. (c) 2006 Elsevier B.V. All rights reserved.