CN101409086B

CN101409086B - Stibium bismuth phase-change alloy mask read-only ultra-resolution CD-disc

Info

Publication number: CN101409086B
Application number: CN2008102029742A
Authority: CN
Inventors: 姜来新; 吴谊群; 王阳; 魏劲松
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2008-11-19
Filing date: 2008-11-19
Publication date: 2010-06-09
Anticipated expiration: 2028-11-19
Also published as: CN101409086A

Abstract

A antimony and bismuth intersection alloy mask read-only super-resolution CD structurally comprises a dielectric layer, a mask layer and a disk base and is characterized in that the dielectric layer consists of silicon nitride; the mask layer consists of antimony and bismuth alloy, that is, SbxBi(1-x) film, wherein, the variation range of x is from 0.7-0.9. The super-resolution CD is characterizedby simple structure, low read-out power, high sensibility, good read-out cyclicity, etc.

Description

The stibium bismuth phase-change alloy mask read-only ultra-resolution CD

Technical field

The invention belongs to the infotech optical storage field, is a kind of stibium bismuth phase-change alloy mask read-only ultra-resolution CD.Compare with currently used mask material, antimony bismuth of the present invention intersects alloy mask read-only ultra-resolution CD-disc, has simple in structurely, and read-out power is low, and is highly sensitive, reads characteristics such as cyclicity preferably, has important application prospects.

Background technology

Along with the development of HIGH-DENSITY OPTICAL STORAGE technology, the information measuring point is more and more littler, has been significantly smaller than the diffraction limit of optical head.In optical storage field, the sensing technique of information is depended in the raising of storage density to a great extent.When the information point of record when very little, when including two or more measuring point in the hot spot that is read laser, information will can not differentiated and be read out.The super-resolution sensing technique may be an important development direction of optical storage technology of future generation, has very important using value and meaning.Use Ge-Sb-Te (GeSbTe) films such as Yasuda realize at first that as mask the super-resolution of read-only disc reads, and see Yasuda K, Ono M, Aratani K, FukumotoA and Kaneko M 1993 Jpn.J.Appl.Phys.325210.Mask material plays an important role in super resolution technology.People use antimony (Sb), silver indium antimony tellurium (AgInSbTe) and platinum oxide (PtO subsequently _x) wait as mask material, referring to Wei J S, Ruan H, Shi H R and GanF X 2002 Chin.Sci.Bull.47 1604; Zhang F, Wang Y, Xu W D and Gan F X2005 Opt.Eng.445.Yet because super resolution optical disc is more than the normal optical disk number of plies, structure is more complicated, so that required record and read-out power are all very high.The read-out power of the read-only ultra-resolution CD-disc that above-mentioned mask constitutes is far longer than the read-out power of common read-only disc 0.5mW all greater than 3mW.High read-out power produces high thermal accumlation, causes atom diffusion in the rete, information measuring point to destroy, read the reduction of cycle index, the serviceable life of reducing CD greatly.The mask material of seeking a kind of low read-out power seems particularly important.

Summary of the invention

Problem to be solved by this invention is to overcome the too high technological deficiency that causes read-only ultra-resolution CD-disc quality and life-span decline of above-mentioned existing read-out power, propose a kind of stibium bismuth phase-change alloy mask read-only ultra-resolution CD, that this CD should have is simple in structure, read-out power is low, highly sensitive and read cyclicity preferably.

Technical solution of the present invention is as follows:

A kind of stibium bismuth phase-change alloy mask read-only ultra-resolution CD, its structure comprise dielectric layer, mask layer and dish base, it is characterized in that described dielectric layer is made of silicon nitride; Described mask layer is by the antimony bismuth alloy, and promptly SbxBi (1-x) film constitutes, and wherein the variation range of x value is 0.7～0.9.

Described mask layer 02 thickness is 30～90nm.This mask layer 02 is used for reading less than the super-resolution of the point of diffraction limit.

The thickness of described dielectric layer 01 is 20～100nm.This dielectric layer 01 be used to improve mask layer 02 stability, prevent its oxidation.

Technique effect of the present invention:

Compare with previous technology, experiment shows: stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention is that 780nm, numerical aperture (NA) are the measuring point that (this device spot diameter is 1.22 λ/NA ≈ 2100nm) read 380nm on 0.45 the dynamic checkout unit in optical maser wavelength (λ).And it compares with the read-only ultra-resolution CD-disc of previous mask material, realizing having lower read-out power when super-resolution is read, is 0.5mW, and the read-out power of this and present common read-only disc is the same.And the read-out power of the read-only ultra-resolution CD-disc of at present used mask material all is 4mW generally all greater than 3mW such as Sb and AgInSbTe.High read-out power can produce high thermal accumlation, causes atom diffusion in the rete, information measuring point to destroy, read the reduction of cycle index, the serviceable life of finally reducing CD.Stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention has well solved this technical barrier.This is because antimony bismuth alloy film is a kind of solid-state and very high material of molten state contrast, and in the CD rotation process, luminous point is anterior because the coincidence temperature between hot spot is higher, and surpassing fusing point is to form the molten state district, and low at the rear part temperature of luminous point be solid-state district.Because the reflectivity of the molten state of antimony bismuth film will be lower than solid-state reflectivity, have only luminous point rear portion information to reflex to receiver like this, and the information of luminous point front molten state has been covered, so luminous point is effectively reduced to have reached the effect of super-resolution.Antimony bismuth film not only plays mask layer but also play the reflection horizon at this.Because the fusing point of antimony bismuth alloy film is lower, be about 325 ℃ again, only need lower read-out power just can realize reading of super-resolution.

Stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention has simple in structurely, and read-out power is low, and is highly sensitive, reads characteristics such as cyclicity preferably, has important application prospects.

Description of drawings

Fig. 1 is the structural drawing of stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention.

Fig. 2 is the dish base of stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention.

Fig. 3 is the used dynamic checkout unit figure of the present invention.

Fig. 4 is the relation that stibium bismuth phase-change alloy mask read-only ultra-resolution CD embodiment of the present invention reads signal to noise ratio (S/N ratio) and read-out power.

Fig. 5 is the relation that stibium bismuth phase-change alloy mask read-only ultra-resolution CD embodiment of the present invention reads signal to noise ratio (S/N ratio) and mask layer thickness.

Embodiment

The invention will be further described below in conjunction with embodiment and accompanying drawing, but should not limit protection scope of the present invention with this.

See also Fig. 1 earlier, Fig. 1 is the structural drawing of stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention.As seen from the figure, stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention, its structure comprises dielectric layer 01, mask layer 02 and dish base 03, described dielectric layer 01 is made of silicon nitride; Described mask layer 02 is by the antimony bismuth alloy, and promptly SbxBi (1-x) film constitutes, and wherein the variation range of x value is 0.7～0.9.

At thickness be on the polycarbonate disc base 03 of 1.2mm prefabricated diameter be the hole point of 380nm as information point, see Fig. 2.The preparation process of stibium bismuth phase-change alloy mask read-only ultra-resolution CD is as follows: (air pressure of sputter is 7.0 * 10 to the method for employing magnetron sputtering ^-4Pa), sputter successively on dish base 03 as shown in Figure 2: alloy mask layer 02 and dielectric layer 01, wherein dielectric layer 01 is the thick silicon nitride of 30nm, alloy mask layer 02 is the thick antimony bismuth alloy SbxBi (1-x) of 10-170nm, wherein the x value is 0.7,0.8 and 0.9, has made multi-disk optical disk.

Dynamic readout device such as Fig. 3, semiconductor laser 1 wavelength (λ) is that 780nm, numerical aperture (NA) are 0.45.Laser beam shines on the CD 8 that is driven by motor 9 through catoptron 6 by polaroid 2 and off beam spectroscope 4.When light beam shines information point again with the reflected light form through the reflection of catoptron 6, off

beam spectroscope

4 and 5, pass polaroid 3 message recipient 10 passed in the variation of reflectivity.To dynamically read diffraction limit formula λ/(4NA) according to CD and calculate and be 433nm, and surpass the measuring point diameter 380nm of Fig. 2, the read-only optical disc that tradition is done the reflection horizon with aluminium can not get any signal.And antimony bismuth mask read-only formula CD of the present invention can be read higher signal.Be that mask layer optimization of seven groups of different-thickness is read signal to noise ratio (S/N ratio) in 0.9 the 10-170nm scope by x value relatively, as Fig. 5, discovery mask layer optimum thickness is 30-90nm.Stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention is not only realized reading of super-resolution but also has significantly been reduced read-out power.As Fig. 4, when read-out power is 0.5mW, obtain very big signal to noise ratio (S/N ratio), and keep signal to noise ratio (S/N ratio) stable with the increasing of power, reached and the same read-out power of present common read-only disc.This mainly is because antimony bismuth alloy film is compared with the mask material (Sb film melting point is higher than 600 ℃, and AgInSbTe is 482 ℃) that occurs at present, has low melting point (～325 ℃).Stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention in addition is after the circulation above 4500 times is read, and signal to noise ratio (S/N ratio) is constant substantially.The x value is respectively 0.7 to be had to x with 0.8 antimony bismuth alloy mask to be that 0.9 antimony bismuth alloy mask has similar super-resolution and reads effect, to read cycle index and be respectively more than 4000 times and 4300 times that concrete outcome sees Table 1.For antimony bismuth alloy SbxBi (1-x), the x value is higher greater than 0.9 o'clock, and the fusing point of alloy film is higher, causes read-out power to raise; And be worth less than 0.7 o'clock, along with the increase of bismuth in the alloy film, mask stability reduces, and causes super resolution optical disc to read cycle index and reduces.Take all factors into consideration, the optimum range of x value is between 0.7-0.9.The dielectric layer silicon nitride plays the protection mask, is 0.7,0.8 and 0.9 alloy mask for the x value, and its optimum thickness range is all 20-100nm, sees Table 1.This shows that stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention just can be realized reading of super-resolution under lower power, avoid because the dish base that high read-out power caused is out of shape the measuring point destruction and the reduction in CD life-span.

In sum, stibium bismuth phase-change alloy mask read-only ultra-resolution CD of the present invention has good super-resolution and reads performance; Have the read-out power more much lower than the read-only disc of current mask material, almost the same with common read-only disc; Information is read stable, reads the cycle index height.Therefore has important application prospects in optical storage field.

Table 1

The X value	Optimum thickness range	Minimum read-out power	Read cycle index	Best thickness of dielectric layers
The X value	Optimum thickness range	Minimum read-out power	Read cycle index	Best thickness of dielectric layers	0.9	30-90nm	0.5mW	≥4500	20-100nm
0.8	30-100nm	0.5mW	≥4300	20-100nm	0.9	30-90nm	0.5mW	≥4500	20-100nm
0.8	30-100nm	0.5mW	≥4300	20-100nm	0.7	25-110nm	0.5mW	≥4000	20-100nm

Claims

1. stibium bismuth phase-change alloy mask read-only ultra-resolution CD, its structure comprise dielectric layer (01), mask layer (02) and dish base (03), it is characterized in that described dielectric layer (01) is made of silicon nitride; Described mask layer (02) is by antimony bismuth alloy, i.e. Sb _xBi _1-xFilm constitutes, and wherein the variation range of x value is 0.7～0.9.

2. antimony bismuth alloy mask read-only ultra-resolution CD-disc according to claim 1 is characterized in that described mask layer (02) thickness is 30～90nm.

3. antimony bismuth alloy mask read-only ultra-resolution CD-disc according to claim 1, the thickness that it is characterized in that described dielectric layer (01) is 20～100nm.