METHOD FOR MANUFACTURING OF ELECTRICAL CONTACTS ON A SOLAR CELL, SOLAR CELL, AND METHOD FOR MANUFACTURING A REAR SIDE CONTACT OF A SOLAR CELL
In various embodiments, a method for manufacturing of electrical contacts on a solar cell is provided. The method may include forming a dielectric layer on a region to be electrically contacted; forming a first metal layer over the dielectric layer; forming electrical contacts between the first metal layer and the region to be electrically contacted through the dielectric layer by laser pulses; annealing the formed electrical contacts; and forming a second metal layer comprising a solderable material at least over a portion of the first metal layer.
1 . A method for manufacturing of electrical contacts on a solar cell, the method comprising:
forming a dielectric layer on a region to be electrically contacted;
forming a first metal layer over the dielectric layer;
forming electrical contacts between the first metal layer and the region to be electrically contacted through the dielectric layer by laser pulses;
annealing the formed electrical contacts; and
forming a second metal layer comprising a solderable material at least over a portion of the first metal layer.
2 . The method of claim 1 ,
wherein the dielectric layer is formed by means of at least one of the following processes: thermal deposition, atomic layer deposition, chemical vapor deposition, or sputtering.
3 . The method of claim 1 ,
wherein the dielectric layer comprises at least one of silicon, silicon nitride, silicon oxide, silicon carbide or aluminum oxide.
4 . The method of claim 1 ,
wherein forming the first metal layer over the dielectric layer is carried out in a vacuum atmosphere.
5 . The method of claim 1 ,
wherein forming the first metal layer over the dielectric layer comprises forming the first metal layer over the dielectric layer by thermal evaporation, E-beam evaporation or sputtering.
6 . The method of claim 1 ,
wherein the solderable material comprises a material selected from a group of: nickel; nickel vanadium; chrome; nickel chrome.
7 . The method of claim 1 ,
wherein forming the second metal layer comprising a solderable material at least over a portion of the metal layer is carried out in a vacuum atmosphere.
8 . The method of claim 1 ,
wherein forming the second metal layer comprising a solderable material at least over a portion of the first metal layer comprises sputtering the layer comprising a solderable material.
9 . The method of claim 1 , further comprising:
removing a metal oxide formed from a portion of the first metal layer, e.g. by plasma treatment in a vacuum atmosphere.
10 . The method of claim 9 ,
wherein after having removed the metal oxide, a layer of the first metal is deposited, e.g. sputtered on the first metal layer.
11 . The method of claim 1 ,
wherein electrical contacts are formed only outside pre-defined solder pad positions.
12 . The method of claim 11 ,
wherein the second metal layer comprising the solderable material is formed only at pre-defined solder pad positions using a mask.
13 . The method of claim 1 , further comprising:
forming a solder contact between a contact wire and the second metal layer comprising the solderable material.
14 . A solar cell having a front side and a rear side, the solar cell comprising:
a dielectric layer on the rear side of the solar cell;
a first metal layer on the dielectric layer;
laser fired contacts forming electrical contacts between the first metal layer and the rear side of the solar cell through the dielectric layer;
a second meal layer comprising solderable material at least over a portion of the first metal layer.
15 . The solar cell of claim 14 ,
wherein the dielectric layer comprises at least one of silicon, silicon nitride, silicon oxide, silicon carbide, and aluminum oxide.
16 . The solar cell of claim 14 ,
wherein the first metal layer comprises at least one metal selected from a group of metals consisting of: aluminum; silver; and gold.
17 . The solar cell of claim 14 ,
wherein the solderable material comprises a material selected from a group of: nickel; nickel vanadium; chrome; nickel chrome.
18 . The solar cell of claim 14 ,
wherein the electrical contacts are formed only outside of pre-defined solder pad positions.
19 . The solar cell of claim 14 ,
wherein the solderable material is formed only on pre-defined solder pad positions.
20 . A method for manufacturing a rear side contact of a solar cell, the method comprising:
forming a dielectric coating on a rear side of a base region of the solar cell;
forming a metal over the dielectric coating;
carrying out a laser firing contact process to form an electrical contact between the metal and the rear side of the base region through the dielectric;
annealing the formed electrical contact; and
forming solderable material at least over a portion of the metal.