High-efficiency solar cell structures and methods of manufacture

Abstract

Solar cells of varying composition are disclosed, generally including a central substrate, conductive layer(s), antireflection layers(s), passivation layer(s) and/or electrode(s). Multifunctional layers provide combined functions of passivation, transparency, sufficient conductivity for vertical carrier flow, the junction, and/or varying degrees of anti-reflectivity. Improved manufacturing methods including single-side CVD deposition processes and thermal treatment for layer formation and/or conversion are also disclosed.

What is claimed is: 
     
         1 . A solar cell comprising:
 a substrate;   an interface passivation layer over the substrate, the interface passivation layer comprising a conductive dopant diffused throughout;   a passivating film over the interface passivation layer, the passivating film comprising a passivating material and the conductive dopant, wherein the passivating film is at least partially crystallized; and   at least one electrode over the passivating film, the conductive dopant within the passivating film and throughout the interface passivation layer providing direct electrical connection between the at least one electrode and the substrate.   
     
     
         2 . The solar cell of  claim 1 , wherein the interface passivation layer has a thickness that permits tunneling of electrical carriers through the interface passivation layer. 
     
     
         3 . The solar cell of  claim 1 , wherein the conductive dopant of the passivating film is diffused into at least a portion of the substrate. 
     
     
         4 . The solar cell of  claim 1 , further comprising an antireflective layer over the passivating film. 
     
     
         5 . The solar cell of  claim 1 , further comprising at least one conductive film over the passivating film, wherein the at least one electrode contacts the at least one conductive film. 
     
     
         6 . The solar cell of  claim 5 , wherein the at least one conductive film is a transparent conductive film. 
     
     
         7 . The solar cell of  claim 1 , wherein the at least one electrode does not penetrate through the passivating film. 
     
     
         8 . A method of fabricating a solar cell, comprising:
 providing a substrate;   providing a passivating film above the substrate, the passivating film comprising a conductive dopant and an oxygen dopant;   thermally treating the passivating film, the thermally treating separating the passivating film into a multilayer passivating film comprising a non-conductive, oxide layer at the substrate and a conductive layer over the non-conductive, oxide layer, and the thermally treating further diffusing a portion of the conductive dopant of the passivating film into the non-conductive, oxide layer; and   providing at least one electrode over the conductive layer of the multilayer passivating film, wherein the conductive dopant of the multilayer passivating film facilitates electrical connection between the at least one electrode and the substrate through the conductive layer and non-conductive, oxide layer of the multilayer passivating film.   
     
     
         9 . The method of  claim 8 , wherein the thermally treating further crystallizes, at least in part, the conductive layer to establish a crystallized passivating layer of the multilayer passivating film. 
     
     
         10 . The method of  claim 9 , wherein the non-conductive, oxide layer of the multilayer passivating film protects the substrate from crystallization during the thermally treating of the passivating film. 
     
     
         11 . The method of  claim 9 , wherein the crystallized passivating layer is a transparent film layer. 
     
     
         12 . The method of  claim 11 , wherein the non-conductive, oxide layer of the multilayer passivating film protects the substrate from crystallization during the thermally treating of the passivating film. 
     
     
         13 . The method of  claim 8 , wherein the diffusing the portion of the conductive dopant further comprises diffusing the portion of the conductive dopant throughout the non-conductive, oxide layer and into the substrate. 
     
     
         14 . The method of  claim 13 , wherein the thermally treating further perforates the non-conductive, oxide layer of the multilayer passivating film to allow electrical carrier transport there-through. 
     
     
         15 . The method of  claim 8 , wherein the non-conductive, oxide layer has a thickness selected to permit tunneling of electrical carriers through the non-conductive, oxide layer. 
     
     
         16 . The method of  claim 8 , wherein the conductive layer of the multilayer passivating film comprises one or more of silicon, silicon-carbide, or diamond-like carbon. 
     
     
         17 . The method of  claim 8 , wherein the conductive dopant of the conductive layer of the multilayer passivating film comprises one or more of boron, nitrogen, phosphorous, aluminum, or gallium. 
     
     
         18 . The method of  claim 8 , further comprising providing at least one conductive film over the conductive layer of the multilayer passivating film, wherein providing at least one electrode over the conductive layer of the multilayer passivating film comprises providing the at least one electrode on the at least one conductive film. 
     
     
         19 . The method of  claim 18 , wherein the at least one conductive film comprises a transparent conductive film. 
     
     
         20 . The method of  claim 8 , wherein providing the at least one electrode comprises providing metallization as electrodes which directly contact the conductive layer over the multilayer passivating film following the thermal treatment thereof, wherein the conductive dopant diffused through the multilayer passivating film provides shortened charge carrier flow paths between the substrate and the electrodes through the conductive layer and the non-conductive, oxide layer of the multilayer passivating film.