Patent Application
20080220197
1. Field of Invention
The present invention relates to a phase-change recording film, and more particularly to a phase-change recording film with stable crystallization rate that does not change as the phase-change recording film thickness varies.
2. Description of the Related Art
A conventional phase-change disc or recording medium comprises a first dielectric film, a phase-change recording film, a second dielectric film and a metal film that are plated sequentially on a polycarbonate substrate with multiple grooves. Then a protective resin layer covers the metal film.
The phase-change disc uses lasers to hit the phase-change recording film and to change a phase of the phase-change recording film between crystalline phase and amorphous phase. Thus, a difference of reflectivity between crystalline phase and amorphous phase is detected to recognize digital signals. When the phase-change recording film is hit by a pulse of a high power laser, the phase-change recording film locally melts and then rapidly cools down to form an amorphous structure. Accordingly, data are written into the phase-change disc. When the phase-change recording film is hit by a pulse of a low power laser, the phase-change recording film is recrystallized locally. Accordingly, data are erased from the phase-change disc.
In order to write and erase data with low power and short pulse and allow the phase-change disc to be written and erased repeatedly, the difference of reflectivity between crystalline phase and amorphous phase of the phase-change recording film has to be significantly large. Additionally, the phase-change recording film has to be sandwiched between two dielectric films to avoid a problem of heat dissipation. Therefore, manufacturing the conventional phase-change disc requires to plate multiple films, which is complicated and takes more time.
Moreover, crystallization rate of the conventional phase-change recording film is related closely to a thickness of the phase-change recording film. With reference to
To overcome the shortcomings, the present invention provides a phase-change recording film with stable crystallization rate, target and process for producing the film to mitigate or obviate the aforementioned problems.
The primary objective of the present invention is to provide a phase-change recording film with stable crystallization rate that does not change as the phase-change recording film thickness varies. The present invention also provides targets and process for producing the phase-change recording film.
A phase-change recording film in accordance with the present invention is composed of 10 to 50 atomic percent of phase-change material containing Te or Sb and 50 to 90 atomic percent of dielectric material.
A composite target for producing the phase-change recording film in accordance with the present invention is composed of 10 to 50 atomic percent of phase-change material containing Te or Sb and 50 to 90 atomic percent of dielectric material.
A target for producing the phase-change recording film in accordance with the present invention is composed of a substrate made of a dielectric material and having a surface and at least one sheet made of a phase-change material containing Te or Sb and attached to the surface of the substrate.
A co-sputtering process for producing the phase-change recording film in accordance with the present invention uses a target made of a dielectric material and a target made of a phase-change material containing Te or Sb to co-sputter.
Because the phase-change recording film in accordance with the present invention has a stable crystallization rate, manufacturing processes of the phase-change recording film needs not to be precisely controlled unduly and manufacturing costs can be lowered.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
With reference to
The phase-change recording film (10) can be manufactured with a target-attached sputtering process, a co-sputtering process using two targets or a sputtering process using a composite target.
The target-attached sputtering process uses a target (20) composed of a substrate (22) made of dielectric material (12) and at least one sheet (22) made of phase-change material (11) containing Te or Sb. The substrate (22) has a surface. The at least one sheet (21) is attached to the surface of the substrate (21). Then the target (20) is sputtered and the dielectric material (12) and the phase-change material (11) are deposited on a disc such as a polycarbonate disc to form a phase-change recording film (10) with stable crystallization rate. The phase-change material (11) containing Te or Sb may be GeSbTe, AgInSbTe, SbTe, GaInSbTe or GeTe. The dielectric material (12) may be Ta2O5, Si3N4, ZnS, SiO2 or a mixture thereof.
With reference to
With reference to
The following examples further illustrate the present invention but are not to be construed as limiting the invention as defined in the claims appended hereto.
SiO2 serves as a substrate of a target and a sheet of AgInSbTe is attached to a surface of the substrate. An area ratio of AgInSbTe to the substrate is 30 percent. The attached target is RF (radio frequency) sputtered with a sputtering power of 100 W in a sputtering gas of Ar at a flow rate of 10 sccm under a work pressure of 3 mtorr to form a phase-change recording film with various thicknesses (20, 30, 40, 50, 60, 90 and 100 nm). With reference to
A target of AgInSbTe or GeSbTe and a target of SiO2 or ZnS—SiO2 are RF co-sputtered simultaneously in a sputtering gas of Ar at a flow rate of 10 sccm under a work pressure of 3 mtorr to form a phase-change recording film with various thicknesses (20, 30, 40, 50, 60, 90 and 100 nm). The target of SiO2 or ZnS—SiO2 is sputtered with a sputtering power of 25 W to 50 W. The target of AgInSbTe or GeSbTe is sputtered with a sputtering power of 100 W to 150 W.
A composite target is formed with a dielectric material such as Ta2O5, Si3N4, ZnS, SiO2 or a mixture thereof and a phase-change material such as GeSbTe, AgInSbTe, SbTe, GaInSbTe or GeTe by powder metallurgy. The powder metallurgy is performed at a temperature of 400° C. to 1000° C. under a pressure of 4500 psi to 15000 psi. The composite target is sputtered to form a phase-change recording film.
With reference to
With reference to
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 096107492 | Mar 2007 | TW | national |
