Effects of oxygen or nitrogen doping on the microstructures, bonding, electrical, thermal properties and phase change kinetics of GeSb9 films

This study investigated the phase change kinetics, thermal, structural, electrical properties, and chemical bonding state of 50-nm-thick oxygen or nitrogen doped GeSb9 films prepared by sputtering. Up to 6.8 at.% O or 8.7 at.% N doping, as measured by secondary ion mass spectrometry, the crystallization temperatures, lattice constants, and the resistivity of both crystalline and amorphous films increased with oxygen or nitrogen concentration , while the grain sizes decreased. Nitrogen atoms bonded to Ge and formed GeN4 nitrides, and both the GeO2 and Sb2O3 co-existed when oxygen concentration reached 8.5 at.%. Crystallization could be triggered by a laser pulse of duration 12 ns for all films. Both GeSb9–O and GeSb9–N films had fast crystallization speed, good thermal stability, and improved resistivity and are therefore potential candidates as active layers for phase-change memory.