Abstract
Tellurium and oxygen co-doped GeSb 9 films (denoted as GeSb 9 -Te/O) with fixed Te concentration for phase change random access memory (PRAM) are investigated. The crystallization temperatures increased from 169°C to 201°C and the crystallization activation energy decreased from 5.53 eV to 2.89 eV as the oxygen concentration increased from 0 at.% to 17.3 at.%.The structures of crystalline GeSb 9 -Te/O films annealed at 250°C are identified as Sb rhombohedral structure with oxygen concentration less than 18 at.%, and the lattice parameter increased from 4.48 Å to 4.52 Å as the oxygen concentration increased from 0 at.% to 17.3 at.%. The grain size became smaller after oxygen doping. For films with oxygen concentration below 6 at.% and annealed at 250°C, only some of Ge form germanium suboxide GeO x , others remain metallic state. In films with oxygen concentration 28.1 at.% and annealed at 250°C, the GeO 2 bond and Sb 2 O 3 bond co-existed. The resistivity of amorphous phase (or crystalline phase) increases from 5.17 Ω-cm to 24.81 Ω-cm (or 1.12×10 -4 Ω-cm to 1.05×10 -3 Ω-cm), about 4.8 times (or about 9.4 times) as oxygen concentration increases from 0 at.% to 17.3 at.%. The film properties show beneficial in PRAM application. © 2008 Materials Research Society.