Influence of interfaces and doping on the crystallization temperature of Ge–Sb

The crystallization temperature Tx of the phase change material Ge–Sb as a function of film thickness and cladding material was measured using time-resolved x-ray diffraction. For films >5 nm, a weak influence of the cladding material on Tx was found (increase for Si, SiN, Pt, SiC, and TiN and decrease for Al and W). For very thin films, however, Tx differed up to 200 °C. Doping of Ge–Sb with these materials led to an increase in Tx in all cases, up to a maximum of 180 °C for SiN. Such a large influence of interfaces and doping on Tx is of great technological importance.