Abstract
This experiment has two parts. The first part is the study of phase change recording materials by using a melt-spinning rapid-solidification-process (RSP) process. The second part is the study of dynamic read-write behavior of the disks whose recording layer materials are Ge4Sb0.5Te5Bi0.5、Ge4Sb0.5Te5Bi0.5Bx, x=0.89at%、Ge2Sb1.5Te5Bi0.5 and Ge2Sb1.5Te5Bi0.5Bx, x=1.27at% developed by our lab. 100% amorphous state is not possible even the maximum wheel speed, 50m/s. In RSP process, because the phase change material has low melting point and high fluidity. In the dynamic testing of the disk, the recording materials were found to become amorphous easier and CNR signals would be larger when the thickness of the reflective layer was increased. However as the thickness of the reflective layer was increased, the recording media cannot absorb enough heat to be crystallized. So the best erasing power was increased, the erase laser power needed was higher. When boron was added in the recording layer, the reflective difference between amorphous and crystalline states increased. Then the CNR values of the disk were increased by 4dB. The four recording materials developed by our lab are good in the writing of 3T signals. After an overwrite cycle of 105 in the writing of 3T signals, the disks still showed high CNR values (25dB and higher). Performance in 14T signals was not satisfactory due mainly to a film structure yet to the optimized.