GeCu Thin Films for Inorganic Write-Once Media

Abstract

The Ge 100 x Cu x thin films (x = 50 at %-69 at %) were deposited on nature oxidized Si (100) wafer by dc co-sputtering of Ge and Cu targets. Microstructures was analyzed by X-ray diffractometer. The optical and thermal properties were measured from static test. It was found that the as-deposited phase was single supersaturated -Cu 3 Ge phase and it was transformed to Ge and -Cu 3 Ge coexisting phases after annealing at 400 C. The reflectivity of as-deposited film was higher than that of annealed film.

Ge/NiGe bilayer applied for the recording film of write-once blu-ray disc

“…Additionally, the crystallization temperature of Ge and disc performance of Ge/Au [10], a-Ge/Ni [11], GeCu [12] and Ge/NiGe (this work) recording layers were compared. It can be found that the decrease in the crystallization temperature of Ge was more obvious in the Ge/NiGe layer.…”

“…Up to now, several metal/Ge bilayers (Ge/Au [10] and a-Ge/Ni [11]) and Ge-metal alloy layers [12] have been fabricated as the recording layers for write-once optical recording applications using a wavelength of 405 nm. In our previous study, the Ge 100Àx Cu x thin films (x ¼ 50 at.%e69 at.%) were deposited by using co-sputtering of Ge and Cu targets.…”

Selective chemical vapor synthesis of Cu3Ge: Process optimization and film properties

“…The Ge phase impurity appears to be more pronounced at higher temperatures, as new peaks of Ge starts appearing from 300 C onwards. The intensity of the Cu 3 Ge (002) peak diminishing at 400 C might indicate either the instability of the formed Cu 3 Ge, the effect of additional Ge into Cu 3 Ge or diffusion induced segregation of the Ge from the solid Cu 3 Ge [19,22,30]. Similarly as to the partial pressure dependency, also the optimal soak temperature depends on the thickness of the Cu utilized.…”

“…In particular, Cu 3 Ge has been suggested as a contact metal in advanced p-type metal-insulator-semiconductor field-effect transistors [7,17]. Furthermore, Cu 3 Ge is a promising material for recording layers in write-once blue-ray discs because of its optical properties [18,19]. The possibility of exploiting Cu 3 Ge layers for metallization of superconductors YBa 2 Cu 3 O 7Àx films is also reported in the literature [20,21].…”

Crystallization mechanism and recording characteristics of GeCu/Si bilayer for write-once blue laser optical recording

“…On the other hand, amorphous germanium (a-Ge) has the similar physical and chemical properties as Si, and the crystallization temperature of a-Ge is only 450 °C [2], which is much lower than that of a-Si. In our previous works, metal/Ge bilayer and metal-doped Ge single layer, such as Ge/Au [3] and GeCu [4] recording films were proposed for use in write-once blue laser optical disc.…”