Via structures in solar cells with bypass diode

Abstract

A solar cell including a semiconductor body with a multijunction solar cell and an integral bypass diode, at least one via extending between the upper and lower surfaces of the semiconductor body and electrically conducting elements of the solar cell.

1 . A solar cell comprising:
 a substrate with a first side and an opposing second side, the second side having a first section at least partly covered by an insulative material and an adjacent second section;   a sequence of layers of semiconductor material and a bypass diode each on the first side of the substrate, the sequence of layers of semiconductor material being separated into a first region forming a multijunction solar cell with a plurality of subcells and a second region forming a support for the bypass diode;   a first contact disposed on the first section of the second side of the substrate on the insulative material;   a second contact disposed on the second section of the second side of the substrate so that the second contact is electrically connected to the multijunction solar cell through the substrate;   a first electrically conducting via extending through the bypass diode, the second region of the sequence of layers of semiconductor material and the substrate to the first contact, the first via electrically connecting the first contact to the bypass diode.   
     
     
         2 . The solar cell of  claim 1 , further comprising:
 a third contact disposed on the first section of the second side of the substrate and spaced apart from the first contact;   an electrical connection extending between the first contact and the third contact; and   a second electrically conducting via extending through the first region of the sequence of layers of semiconductor material and the substrate to the third contact, the second via electrically connecting a top subcell of the multijunction solar cell to the third contact so that a first terminal of the bypass diode and the top subcell are electrically connected.   
     
     
         3 . The solar cell of  claim 1 , further comprising:
 a plurality of additional spaced-apart contacts disposed on the first section of the second side of the substrate;   an electrical connection extending between each one of the additional contacts and the first contact; and   a plurality of electrically conducting vias extending through the first region of the sequence of layers of semiconductor material and the substrate to individual ones of the additional contacts so that a top subcell of the multijunction solar cell and a first terminal of the bypass diode are electrically connected.   
     
     
         4 . The solar cell of  claim 1 , further comprising a trench that extends through the sequence of layers of semiconductor material to the substrate and separates the first region and the second region. 
     
     
         5 . The solar cell of  claim 4 , further comprising an electrically conductive shunt that extends into the trench and electrically connects a first terminal of the bypass diode to a bottom subcell of the multijunction solar cell. 
     
     
         6 . The solar cell of  claim 5 , wherein the second contact is electrically connected to the bottom subcell through the substrate and to the bypass diode through the substrate and the shunt. 
     
     
         7 . The solar cell of  claim 2 , further comprising a charge collecting grid extending over the first region of the sequence of layers of semiconductor material, the charge collecting grid facing away from the second side of the substrate and being electrically connected to the third contact on the second side of the substrate through the second via. 
     
     
         8 . A solar cell comprising:
 a substrate with a first side and an opposing second side;   a multijunction solar cell positioned on a first section of the first side of the substrate and having at least a bottom-most cell and a top-most cell with the bottom-most cell in closer proximity to the substrate than the top-most cell;   a bypass diode positioned on a second section of the first side of the substrate and spaced away from the multijunction solar cell;   a top-most layer of the top-most cell of the multijunction solar cell having a conductivity type that is opposite of a top-most layer of the bypass diode; and   an electrically conducting via that extends through the second section of the substrate to electrically connect a top-most layer of the bypass diode to a first contact on the second side of the substrate, the first contact being insulated from the substrate and spaced apart from a second contact on the second side of the substrate, the second contact being electrically connected to the substrate.   
     
     
         9 . The solar cell of  claim 8 , further comprising a second electrically conducting via extending through the multijunction solar cell and the first section of the substrate to electrically connect the top-most cell of the multijunction solar cell to the first contact formed on the second side of the substrate so that the top-most layer of the bypass diode and the top-most cell are electrically connected. 
     
     
         10 . The solar cell of  claim 9 , further comprising a third electrically conducting via extending through the multijunction solar cell and the substrate to electrically connect the top-most cell of the multijunction solar cell to the first contact formed on the second side of the substrate so that the top-most layer of the bypass diode and the top-most cell are electrically connected. 
     
     
         11 . The solar cell of  claim 8 , wherein the top-most layer of the top-most cell of the multijunction solar cell is an emitter layer. 
     
     
         12 . The solar cell of  claim 8 , wherein a bottom-most layer of the bottom-most cell of the multijunction solar cell has a conductivity type that is opposite of a bottom-most layer of the bypass diode. 
     
     
         13 . A solar cell comprising:
 a semiconductor body including a sequence of layers of semiconductor material formed on a first side of a substrate, at least a portion of the sequence of layers of semiconductor material forming a multijunction solar cell in a first region of the semiconductor body with a plurality of cells and at least a portion of the sequence of layers of semiconductor material forming a bypass diode in a second region of the semiconductor body;   the plurality of cells including a top cell with a top-most layer having a conductivity type that is opposite of a top-most layer of the bypass diode and a bottom cell with a bottom-most layer having a conductivity type that is opposite of a bottom-most layer of the bypass diode; and   a first via extending through the sequence of layers of semiconductor material and the substrate in the second region of the semiconductor body, the first via being insulated from the sequence of layers of semiconductor material and electrically connecting the top-most layer of the bypass diode to a first contact formed on an opposing second side of the substrate, the first contact being insulated from the substrate and spaced apart from a second contact on the second side of the substrate, the second contact being electrically connected to the bottom cell through the substrate.   
     
     
         14 . The solar cell of  claim 13 , further comprising a second via extending through the sequence of layers of semiconductor material and the substrate in the first region of the semiconductor body to electrically connect the top cell of the plurality of cells to the first contact formed on the second side of the substrate so that the top-most layer of the bypass diode and the top cell are electrically connected. 
     
     
         15 . The solar cell as defined in  claim 14 , wherein the first via electrically connects an anode of the bypass diode to the first contact formed on the second side of the substrate, and the second via electrically connects an emitter of the top cell of the multijunction solar cell to the first contact formed on the second side of the substrate. 
     
     
         16 . The solar cell as defined in  claim 13 , further including a trench that separates the first and second regions of the semiconductor body. 
     
     
         17 . The solar cell of  claim 13 , further comprising a plurality of additional spaced-apart vias extending through the sequence of layers of semiconductor material and the substrate in the first region of the semiconductor body that electrically connect the top cell of the plurality of cells to the first contact formed on the second side of the substrate so that the top-most layer of the bypass diode and the top cell are electrically connected. 
     
     
         18 . The solar cell of  claim 16 , further comprising a shunt formed in the trench that electrically connects the bottom-most layer of the bypass diode and the bottom-most layer of the bottom cell of the multijunction solar cell. 
     
     
         19 . The solar cell of  claim 18 , wherein the bottom-most layer of the bypass diode is a base layer. 
     
     
         20 . The solar cell of  claim 14 , further comprising a charge collecting grid extending over the multijunction solar cell in the first region, the charge collecting grid facing away from the second side of the substrate and being electrically connected to the first contact through the second via.