Enhancement of data transfer rate of phase change optica disk by doping nitrogen in Ge-In-Sb-Te recording layer

Abstract

This work investigated the enhancement of the data transfer rate and/or recrystallization speed of Ge-In-Sb-Te recording material by nitrogen doping. The effects of nitrogen content on the dynamic properties of optical disks and the corresponding microstructural changes of the recording layer were studied. The experimental results showed that nitrogen doping at a sputtering gas flow ratio of N-2/Ar = 3% might enhance the data transfer rate of an optical disk up to 1.6 times without severely damaging the signal jitter values. However, the disks failed the dynamic tests when too much nitrogen (N-2/Ar greater than or equal to 5%) was introduced. Dynamic testing also revealed that nitrogen doping slightly increased the noise level and jitter of the disks. Transmission electron microscopy (TEM) found that nitrogen doping promoted a phase transformation by generating numerous nucleation sites uniformly distributed in the recording layer and hence increased recrystallization speed.