HIGH-EFFICIENCY PHOTOVOLTAIC BACK-CONTACT SOLAR CELL STRUCTURES AND MANUFACTURING METHODS USING THREE-DIMENSIONAL SEMICONDUCTOR ABSORBERS

1 . A back contact back junction three-dimensional thin solar cell, comprising:

a three-dimensional deposited semiconductor layer having a frontside and a backside, comprising:

a light capturing frontside surface with a passivation layer,

a doped base region, and

a doped backside emitter region with a polarity opposite said doped base region;

a backside passivation layer on said doped backside emitter region;

backside emitter contacts and backside base contacts connected to metal interconnects and selectively formed on three-dimensional features of the backside of said three-dimensional deposited semiconductor layer; and

a transparent frontside permanent support reinforcement on the frontside of said back contact back junction three-dimensional thin solar cell.

2 . The back contact back junction three-dimensional thin solar cell of claim 1 , wherein said deposited semiconductor layer is an epitaxial silicon layer with a thickness in the range of 1 to 30 microns.

3 . The back contact back junction three-dimensional thin solar cell of claim 1 , wherein said doped backside emitter region is an epitaxial in-situ doped emitter region.

4 . The back contact back junction three-dimensional thin solar cell of claim 1 , wherein said backside emitter contacts and backside base contacts are discretely positioned on three-dimensional features of the backside of said three-dimensional deposited semiconductor layer.

5 . The back contact back junction three-dimensional thin solar cell of claim 1 , wherein said backside emitter contacts and backside base contacts are formed in a continuous interdigitated pattern on three-dimensional features of the backside of said three-dimensional deposited semiconductor layer.

7 . The back contact back junction three-dimensional thin solar cell of claim 1 , wherein said light capturing frontside surface with a passivation layer serves as an anti-reflection coating.

8 . The back contact back junction three-dimensional thin solar cell of claim 1 , wherein said light capturing frontside surface with a passivation layer provides field assisted passivation.

9 . The back contact back junction three-dimensional thin solar cell of claim 1 , further comprising a backside reinforcement layer filling cavities of the three-dimensional features on the backside of said three-dimensional thin deposited semiconductor layer.

10 . A back contact back junction three-dimensional thin solar cell, comprising:

a three-dimensional deposited semiconductor layer having a frontside and a backside, said deposited semiconductor layer having an inverted pyramidal structure wherein backside surface ridges define the openings of inverted pyramidal cavities, comprising:

a light capturing frontside surface with a passivation layer,

a doped base region, and

a doped backside emitter region with a polarity opposite said doped base region;

a backside passivation layer on said doped backside emitter region; and

backside emitter contacts and backside base contacts selectively formed on the backside surface ridges of said three-dimensional deposited semiconductor layer and connected to metal interconnects.

11 . The back contact back junction three-dimensional thin solar cell of claim 10 , a transparent permanent frontside support reinforcement on the frontside of said back contact back junction three-dimensional thin solar cell.

12 . The back contact back junction three-dimensional thin solar cell of claim 10 , wherein said deposited semiconductor layer is an epitaxial silicon layer with a thickness in the range of 1 to 30 microns.

13 . The back contact back junction three-dimensional thin solar cell of claim 10 , wherein said doped backside emitter region is an epitaxial in-situ doped emitter region.

14 . The back contact back junction three-dimensional thin solar cell of claim 10 , wherein said inverted pyramidal cavities comprise a plurality of differently sized inverted pyramidal cavities.

15 . The back contact back junction three-dimensional thin solar cell of claim 10 , wherein said inverted pyramidal cavities comprise a set of larger inverted pyramidal cavities and a set of smaller inverted pyramidal cavities.

16 . The back contact back junction three-dimensional thin solar cell of claim 10 , wherein said backside emitter contacts and backside base contacts are discretely positioned on the backside surface ridges of the inverted pyramidal cavities on the backside of said three-dimensional thin deposited semiconductor layer.

17 . The back contact back junction three-dimensional thin solar cell of claim 10 , wherein said backside emitter contacts and backside base contacts are formed on the ridges of the inverted pyramidal cavities on the backside of said three-dimensional thin deposited semiconductor layer in a continuous line pattern.

18 . The back contact back junction three-dimensional thin solar cell of claim 10 , further comprising a backside reinforcement layer at least partially filling cavities of the inverted pyramidal cavities on the backside of said three-dimensional thin deposited semiconductor layer.

19 . A method for the manufacture of a three-dimensional back contact back junction thin solar cell from a crystalline semiconductor layer, the method providing continuous structural support to said crystalline semiconductor layer, the method comprising:

forming a conformal porous semiconductor layer on a three-dimensional template, said three-dimensional template having an inverted pyramidal structure with backside surface ridges defining openings of inverted pyramidal cavities, wherein said template provides structural support and acts as a high temperature temporary carrier for back contact back junction solar cell backside processing steps, said backside processing steps comprising:

depositing a conformal doped base crystalline semiconductor layer on said porous semiconductor layer;

forming a conformal doped emitter layer on said doped base crystalline semiconductor layer;

separating said doped base crystalline semiconductor layer from said template along said porous semiconductor layer, wherein a cell backside reinforcement layer is attached to said solar cell backside prior to release to provide support for cell frontside processing steps, said frontside processing step comprising forming a light capturing frontside surface with a passivation and anti-reflection layer on the frontside of said crystalline semiconductor layer;

attaching a transparent permanent frontside reinforcement support to the cell frontside;

depositing a backside passivation dielectric layer on said doped emitter layer;

forming selective backside base and emitter contact openings through said dielectric layer on the ridges of said inverted pyramidal cavities;

doping exposed regions to form emitter regions and base regions; and

metalizing the cell backside to form backside base and emitter contacts on the ridges of said inverted pyramidal cavities.

20 . The method of claim 19 , wherein said cell backside reinforcement layer serves as a backside diffuse mirror for said three-dimensional back contact back junction thin solar cell.

21 . The method of claim 19 , wherein the step of depositing a doped base crystalline semiconductor layer comprises depositing a doped base epitaxial silicon layer with a thickness in the range of 1 to 30 microns.

22 . The method of claim 19 , wherein the step of forming a doped emitter layer on said doped base crystalline semiconductor layer comprises forming an in-situ doped emitter epitaxial layer.

23 . The method of claim 19 , wherein pulsed duration laser ablation is used to form selective backside base and emitter contact openings through said dielectric layer on the ridges of said inverted pyramidal cavities.

24 . The method of claim 19 , wherein sub-nanosecond pulsed duration laser ablation is used to form selective backside base and emitter contact openings through said dielectric layer on the ridges of said inverted pyramidal cavities.