Memory switching of germanium tellurium amorphous semiconductor

摘要

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 ΔE_σ, the room temperature electrical conductivity σ_(RT) and the pre-exponential factor σ_0 were measured and validated for the tested sample. The conduction activation energy ΔE_σ 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 ΔE_(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 ΔE_R and ΔE_P caused by resistance and power respectively are deduced. The results obtained support thermal model for initiating switching process in this system.