Crystallization Characteristics of SiN_(x)-Doped SbTe Films for Phase Change Memory

SbTe films doped with different SiN_(x) concentrations(2,5,17,25at.%)are prepared by co-sputtering with Si_(3)N_(4) and SbTe alloy targets.In order to study the crystallization process and amorphous state stability and to compare with Ge_(2)Sb_(2)Te_(5)(GST)and pure SbTe films,x-ray diffraction(XRD),transmission electron microscopy(TEM)and in situ film resistance measurements are carried out.SiN_(x)doping enhances the amorphous state stability of the SbTe films.The temperature for 10-year retention of amorphous state of pure SbTe films is-11℃and that of 17at.%SiN_(x)-doped Sb Te films increases to 75℃.SiN_(x) addition increases the crystallization temperature and the electrical resistivity of SbTe films.The microstructures of SiN_(x)-doped SbTe films are analyzed through XRD and TEM.After anneealing at 350℃,SiN_(x)-doped SbTe films crystallized into a kind of nanocomposite films with rhombohedra Sb_(2)Te_(3) nanoparticles embedded into an amorphous SiN_(x) matrix.The nanocomposite structure and higher crystalline resistivity of the SiN_(x)-doped SbTe films is helpful to reduce the RESET current of phase change memory.