Processing method for cleaning sulfur entities of contact regions
View Patent ↗A method for forming a thin film photovoltaic device. The method includes providing a transparent substrate comprising a surface region and forming a first electrode layer overlying the surface region of the transparent substrate. The first electrode layer has an electrode surface region. In a specific embodiment, the method includes masking one or more portions of the electrode surface region using a masking layer to form an exposed region and a blocked region. The method includes forming an absorber layer comprising a sulfur entity overlying the exposed region and removing the mask layer. In a specific embodiment, the method causing formation of a plurality of metal disulfide species overlying the blocked region. In a specific embodiment, the metal disulfide species has a semiconductor characteristic. The method includes subjecting the plurality of metal disulfide species to electromagnetic radiation from a laser beam to substantially remove the metal disulfide species. The method includes exposing the blocked region free and clear from the metal disulfide.
1. A method for forming a thin film photovoltaic device comprising:
providing a transparent substrate having a surface;
forming a first electrode layer over the surface, the first electrode layer having an electrode surface region;
masking the electrode surface region using a masking layer to define an exposed region and a blocked region;
forming an absorber layer, including a sulfur entity, over the exposed region;
removing the masking layer;
exposing a metal disulfide species having a semiconductor characteristic over the blocked region; and
subjecting the metal disulfide species to electromagnetic radiation from a laser to substantially remove the metal disulfide species from the previously blocked region.
2. The method of claim 1 further comprising forming a window layer over the absorber layer.
3. The method of claim 2 further comprising forming a transparent conductive oxide overlying a portion of the window layer.
4. The method of claim 1 wherein the step of forming the absorber layer comprises:
forming a copper layer over the exposed region and an indium layer over the copper layer to thereby form a multi-layered structure;
subjecting the multi-layered structure to heat in an environment containing sulfur to thereby form copper indium disulfide having an atomic ratio of copper to indium between about 1.35 to 1 to about 1.60 to 1.
5. The method of claim 4 wherein the step of subjecting the multi-layered structure to heat also forms a surface layer of copper sulfide on the copper indium disulfide.
6. The method of claim 5 further comprising a step of removing the surface layer of copper sulfide.
7. The method of claim 6 wherein the step of removing the surface layer of copper sulfide comprises using potassium cyanide to selectively remove the copper sulfide.
8. The method of claim 1 wherein the electromagnetic radiation is pulsed.
9. A method for forming a thin film photovoltaic device comprising:
providing a transparent substrate having a surface;
forming a first electrode layer having an electrode surface region over the surface of the transparent substrate;
masking the electrode surface region with a masking layer to define an exposed region and a blocked region;
forming an absorber layer including sulfur over the exposed region;
removing the mask layer;
exposing metal disulfide having a semiconductor characteristic over the blocked region; and
mechanically removing the metal disulfide from the previously blocked region.
10. The method of claim 9 wherein the step of forming the absorber layer comprises:
forming a copper layer over the exposed region and an indium layer over the copper layer to form a multi-layered structure; and
heating the multi-layered structure in an environment containing sulfur to thereby form a copper indium disulfide having an atomic ratio of copper to indium ranging from about 1.35 to 1 to about 1.60 to 1.
11. The method of claim 10 wherein the step of heating also forms a copper sulfide surface region on the copper indium disulfide.
12. The method of claim 11 further comprising using a potassium cyanide solution to remove the copper sulfide.