CN101792897A - High-purity molybdenum target for thin-film solar cell and preparation method thereof - Google Patents

Abstract

The invention aims at providing a high-purity molybdenum target for a thin-film solar cell and a preparation method thereof for increasing the quality of the thin-film solar cell. The high-purity molybdenum target for the thin-film solar cell is prepared by molybdenum plates with the purity degree which is greater than or equal to 99.97 percent, the density which is greater than 10.18g/cm<3> and impurity oxygen content which is less than or equal to 0.004 percent. The high-purity molybdenum target is prepared by the following steps of: preparing high-purity molybdenum trioxide; firstly, carrying out primary reduction by adopting high-purity hydrogen at a temperature of 550-600 DEG C; then, carrying out secondary reduction at a temperature of 950-1000 DEG C; after the reduction, mixing, sieving and isostatically molding sequentially; then, carrying out induction sintering in intermediate frequency at a temperature of 1950-2000 DEG C; hot forging at a temperature of 1400-1450 DEG C; hot rolling at a temperature of 1350-1400 DEG C; processing into the prescriptive specification by a machine finally; checking. The high-purity molybdenum target for the thin-film solar cell has high purity, high density and good uniformity, greatly increases the utilization ratio of sputtering target materials and has higher value in solar cell industry.

Description

High-purity molybdenum target for thin-film solar cell and preparation method thereof

Technical field

The invention belongs to energy utilization technology field, particularly technical field of solar cell manufacturing.

Background technology

Thin-film solar cells is the multi-layer film structure assembly, such as, CIGS (copper-indium-galliun-selenium) thin-film solar cells mainly is made up of substrate (normally glass), dorsum electrode layer (normally Mo), absorption layer (p-CIGS), buffer layer (normally n-CdS), transparency conducting layer (normally ZnO or Al doping ZnO bilayer structure), upper electrode layer (being generally Ni/Al) and antireflection layer (normally MgF2).Here, dorsum electrode layer is one deck molybdenum film (0.5-1.5 μ m is thick) as thin as a wafer, and it is to adopt the technology of sputtered film to be splashed in the substrate by molybdenum target to form.

Generally, the purity of molybdenum target, density and homogeneity of structure are directly connected to the quality and the thickness evenness of plated film, and then have influence on electrode performance the sputter important influence.Simultaneously because dorsum electrode layer is one deck molybdenum film as thin as a wafer, even trickle inclusion all may impact the quality of film in the film, nonmetallic impurity thing especially.These strict demands to coating quality are reflected on the sputtering target, just require the weave construction of sputtering target material and chemical purity should meet corresponding technology.

How to suppress that the generation of particulate is an important factor of guaranteeing coating quality in the sputter procedure.In the process of sputter coating, so-called particulate is meant large-sized target particle or the particulate that produces when sputtering target is subjected to high-energy ion bombardment, or the particulate that the film material is subjected to secondary electron to bombard out to form after the film forming.The generation of these particulates for film forming quality very big influence is arranged, especially require very harsh microelectronic industry for membrane quality.The one of the main reasons of these particulates generations is because the compact structure of sputtering target material is not enough, and the gas that exists in target internal void during sputter release is suddenly caused.The most normal sputtering target made from powder technology (as hot compacting, sintering, pyrolytic coating moulding etc.) that occurs in of the phenomenon of this particulate that splashes.Therefore, how improving the sputtering target density also is one of important technology problem.

In the planar magnetic control sputtering process, because crossed electric and magnetic field is to the interactively of plasma sputter, sputtering target will produce inhomogeneous erosion (Erosion) phenomenon in sputter procedure, thereby the utilization ratio that causes sputtering target material is general usually low, and the utilization ratio of rectangle sputtering target (weight percent) is at 25%-40%.Need more frequent replacing target in the production.Therefore the utilization ratio that how to improve sputtering target material is subjected to greatly paying close attention to.

Summary of the invention

The object of the invention provides a kind of high-purity molybdenum target for thin-film solar cell and preparation method thereof, to improve the quality of solar cell.

High-purity molybdenum target for thin-film solar cell, it is to adopt purity 〉=99.97%, density is greater than 10.18g/cm ³, especially the molybdenum plate of impurity oxygen content≤0.004% is made.

The preparation method of described high-purity molybdenum target for thin-film solar cell, it is to realize according to following steps:

Preparation high purity molybdic oxide at first adopts high-purity hydrogen once to reduce at 550-600 ℃; Then at 950-1000 ℃ of secondary reduction; Pass through batch mixing, screening, isostatic pressing after the reduction successively; Then at 1950-2000 ℃ of following Medium frequency induction sintering; Again 1400-1450 ℃ of forge hot; 1350-1400 ℃ of hot rolling; Be added to regulatory specifications by machinery at last, check gets final product.

Advantage of the present invention is the characteristics that high-purity molybdenum target for thin-film solar cell has high purity, high-density and good homogeneous, has greatly improved the utilization ratio of sputtering target material, is applied to the solar cell industry and has very high value.

Embodiment

The present invention has made improvement to existing target aspect following:

1, purity: well-known, the electroconductibility of metal and the purity of material have substantial connection, the foreign matter content of reduction metal molybdenum, and the content of oxygen especially can improve the heat conduction and the conductivity of molybdenum back electrode.It is O≤0.004% that molybdenum target of the present invention has the oxygen level standard, Mo 〉=99.97% (metal content), and also other impurity is according to following table control (attached common molybdenum plate data simultaneously)

2, density: because molybdenum target adopts the powder metallurgy manufacturing, if inappropriate technology can reduce the density of molybdenum target, serious words can also can cause target tissue looseness, influence the target quality.The described molybdenum target of this patent improves target density by the gross distortion working modulus and eliminates tissue looseness's defective of sintered products.Density can reach 10.2g/cm ³.

3, homogeneity of structure: molybdenum target of the present invention has uniform heat-treated sturcture, is beneficial to obtain the equally distributed plated film of thickness.

Operational path of the present invention: prepare high-purity molybdic oxide-550-600 ℃ once reduction-950-1000 ℃ secondary reduction-batch mixing-screening-isostatic pressing-1950-2000 ℃ Medium frequency induction sintering-1400-1450 ℃ forge hot-1350-1400 ℃ hot rolling-machine add-check.

Claims (3)

1. high-purity molybdenum target for thin-film solar cell is characterized in that adopting purity 〉=99.97%, and density is greater than 10.18g/cm ³, especially the molybdenum plate of impurity oxygen content≤0.004% is made.

2. high-purity molybdenum target for thin-film solar cell according to claim 1 is characterized in that the purity and the foreign matter content of the molybdenum plate that adopted controlled according to following table:

3. the preparation method of high-purity molybdenum target for thin-film solar cell as claimed in claim 1 or 2 is characterized in that realizing according to following steps:

Preparation high purity molybdic oxide at first adopts high-purity hydrogen once to reduce at 550-600 ℃; Then at 950-1000 ℃ of secondary reduction; Pass through batch mixing, screening, isostatic pressing after the reduction successively; Then at 1950-2000 ℃ of following Medium frequency induction sintering; Again 1400-1450 ℃ of forge hot; 1350-1400 ℃ of hot rolling; Be added to regulatory specifications by machinery at last, check gets final product.