Nitrogen and Silicon Co-Doping of Ge₂Sb₂Te₅ Thin Films for Improving Phase Change Memory Performance

Electrical properties and phase structures of (Si+N)-codoped Ge₂Sb₂Te₅ (GST) for phase change memory are investigated to improve the memory erformance. Compared to the films with N or Si dopants only in previous reports, the (Si+N)-doped GST has a remarkable improvement of crystalline resistivity of about 10⁴m Ωcm. The Fourier-transform infrared spectroscopy
spectrum reveals the Si--N bonds formation in the film. X-ray diffraction patterns show that the grain size is reduced due to the crystallization inhibition of the amorphous GST by SiN_x, which results in higher crystalline resistivity. This is very useful to reduce writing current for phase change memory applications.