Mechanisms of Initialization of Doped Sb-Te Phase-Change Media

Abstract

ABSTRACTLaser initialization of the chalcogenide optical-recording medium Ag-In-Sb-Te is investigated using transmission electron microscopy of the resulting microstructure. Initialization beam power and velocity are varied. The average inhomogeneous strain of the chalcogenide is estimated from X-ray peak broadening. At high power and low velocity a clearly defined columnar grain structure with low strain is produced, typical of directional solidification. At low power and high velocity the initialized structure has a high density of defects and high strain; this is attributed to crystallization from the amorphous rather than the liquid state. The beam power and linear velocity of laser initialization may therefore be used to control the microstructure.