Electron beam evaporation deposition and properties of Abrupt GST/Si heterojunction structure

The ternary alloy, Ge2Te2Sb5 is one of the most important compounds of the GeTe-Sb2Te3 pseudobinary systems. Ge2Te2Sb5 thin films of thickness of 100 nm–300 nm were deposited by electron beam evaporation. After annealing at different temperatures, we did X-ray diffraction measurement to characterize the structure transformation of the material. In-situ resistance measurement depending on the temperature shows that there is about three orders of magnitude change between the high resistance state (amorphous state) and the low resistance state (face-centered cubic state). To construct a heterojunction diode, we deposited Ge2Te2Sb5 thin films on n-type silicon wafers. Rectification effects were observed in voltage–current measurements of the abrupt heterojunctions. Traditional voltage–current relationship of p–n junctions and metal-semiconductor junctions are used to explain the characteristics of Ge2Te2Sb5/n-Si heterojunctions.

► Phase-change materials (Ge2Te2Sb5).
► Rectifying characteristics of abrupt GST/Si heterojunction.
► Electron beam evaporation deposition of Ge2Te2Sb5 thin film.