Back-contact photovoltaic cells

A method for making a photovoltaic cell comprising (a) depositing a first passivation layer on a first surface of a wafer comprising a semiconductor material;

• (b) depositing a second passivation layer on a second surface of the wafer;
• (c) depositing over the second passivation layer a layer of semiconductor material having conductivity type opposite the wafer;
• (d) optionally depositing a TCO layer over the layer of semiconductor material;
• (e) depositing a first electrical contact layer over the layer of semiconductor material or, if present, the TCO layer;
• (f) forming a plurality of holes through at least the first electrical contact layer and the TCO layer if present, (g) depositing a layer of insulating material over the first electrical contact layer and into the holes;
• (h) depositing a second electrical contact layer over the insulating layer;
• and (i) forming a plurality of point contacts from the second electrical contact layer to the wafer.

A method for forming an electrical contact between an electrical conducting layer and a second layer, where there is at least a third layer positioned between the electrical conducting layer the second layer, method comprising:

• forming a first opening in the third layer;
• forming an insulating layer comprising an insulating material over the third layer wherein the insulating material fills the first opening,
• forming a second opening in the insulation layer inside an area of the first opening leaving a region of the insulation material along a perimeter of the second opening and where the second opening,
• forming a layer of electrical conducting material over the insulation layer and filling the second opening thereby forming an electrical contact between the electrical conduction layer and the second layer.

A method for making a photovoltaic cell comprising (a) depositing a first passivation layer on a first surface of a wafer comprising a semiconductor material;

• (b) depositing a second passivation layer on a second surface of the wafer;
• (c) depositing over the second passivation layer a layer of semiconductor material having conductivity type opposite the wafer;
• (d) optionally depositing a TCO layer over the layer of semiconductor material having a conductivity opposite the wafer;
• (e) depositing a first electrical contact layer over the semiconductor material having a conductivity opposite the wafer or, if present, the TCO layer;
• (f) removing at least the layers formed in steps (d) and (e) in a desired pattern thereby a exposing an area on the wafer without layers formed in steps (d) and (e);
• (g) depositing third passivation layer over the exposed area formed in step (f);
• (h) optionally depositing a semiconductor layer having a conductivity type the same as the wafer over the third passivation layer;
• (i) optionally depositing a second TCO layer over the third passivation layer or, if present, over the semiconductor layer having a conductivity type the same as the wafer;
• (j) depositing a second electrical contact layer over the third passivation layer or, if present, over the semiconductor layer having a conductivity type the same as the wafer, or, if present, over the second TCO layer;
• (k) forming a gap between the first electrical contact layer and the second electrical contact layer to electrically separate the first electrical contact layer from the second electrical contact layer thereby forming electrically separated electrical contacts.

A method for making a photovoltaic cell comprising (a) depositing a first passivation layer on a first surface of a wafer comprising a semiconductor material;

• (b) forming a first electrical contact on the second surface of the wafer in a desired pattern;
• (c) depositing a second passivation layer on a second surface of the wafer;
• (c) depositing over the second passivation layer a layer of semiconductor material having conductivity type opposite the wafer;
• (d) optionally depositing a TCO layer over the layer of semiconductor material having a conductivity opposite the wafer;
• (e) depositing a second electrical contact layer over the semiconductor material or, if present, the TCO layer;
• (k) forming a gap between the first electrical contact layer and the second electrical contact layer to electrically separate the first electrical contact layer from the second electrical contact layer thereby forming electrically separated electrical contacts.