Effects of high melting point element dopant on the optical properties and microstructure of the GeSbSn phase change optical disk films
Date Issued
2005
Date
2005
Author(s)
Ma, Shih-Hsien
DOI
zh-TW
Abstract
One of the main development in rewritable phase change optical disk is to find out high crystallization speed materials for high-speed phase change optical disk application. In this study, (GeSbSn)100-xMx thin films (M=Ta、Fe、Ru、Ni or Co) are deposited on nature-oxidized Si wafer and glass substrates by DC magnetron co-sputtering. From the thermal analysis, we choose (GeSbSn)100-xFex and (GeSbSn)100-xCox thin films to investigated the effects of Fe or Co on the optical properties and microstructures of these films, and investigate its possibility for rewritable phase change optical media application.
Thermal analysis shows that doping Fe or Co into GeSbSn thin film can decrease the activation energy and phase change temperature of the film. This indicates that the crystallization speed of the GeSbSn film will be increased. The optical property analysis shows that (GeSbSn)100-xFex and (GeSbSn)100-xCox films have good absorption. The optical contrast of (GeSbSn)100-xCox film decreases with increasing Co conent as x = 8.20~16.75. The optical contrast of (GeSbSn)100-xFex film increases with Fe content as x in the range of 7.10~9.75 but decreases with Fe content when x=12.91~16.63. The X-ray diffraction analysis shows that the as-deposited (GeSbSn)100-xFex and (GeSbSn)100-xCox films are amorphous structure. After annealing at 250℃ for 30 min, the major crystalline phase of (GeSbSn)100-xFex film (x=0~9.75) is Sb. The Sb、Fe and FeSb crystalline phases are appeared as x>16.63. After same annealing condition, the Sb and SbCo3 crystalline phase are found in the (GeSbSn)100-xCox film (x>8.20).
The TEM analysis shows that the average grain size of the GeSbSn film is about 27.9 nm after annealing at 250℃ for 30 min. After doping Fe, average grain size of the GeSbSn film is decreased, it decreases to 17.6 nm as 7.10 at.% Fe is added. However, the grain size is increased to about 30.1 nm when 16.63 at.% Fe is added. On the other hands, as 9.79 at.% Co is doped into the GeSbSn film, average grain size of the film is decreased to about 16.8 nm, and the grain shape is irregular. When 16.75 at.% Co is added, the grain grows irregularly, the grain size is in the range of 30 to 200 nm and the average size is about 96 nm.
Subjects
相變化光碟
phase change optical disk
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-94-R92527021-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):d3fbdabca546d80b1ecb67fb3689ea13