Methods of providing liquid material to selected regions of semiconductor material with textured surfaces
Semiconductor photovoltaic cells have surfaces that are textured for processing and photovoltaic reasons. The absorbing regions may have parallel grooves that reduce loss of solar energy that would otherwise be lost by reflection. One form of texturing has parallel grooves and ridges. The cell also includes regions of metallization for collecting the generated electrical carriers and conducting them away, which may be channels. The topography is considered during production, using a process that takes advantage of the topography to govern what locations upon will receive a specific processing, and which locations will not receive such a processing. Liquids are treated directly into zones of the cell. They migrate throughout a zone and act upon the locations contacted. They do not migrate to other zones, due to impediments to fluid flow that are features of the surface texture, such as edges, walls and ridges. Blocking liquid may also be deposited and migrate within a zone, to block or mask a subsequent activity, such as etching.
1. A method for fabricating a semi-conductor device, comprising:
a. forming a topographically textured semiconductor surface of a semiconductor body;
b. forming a junction involving the semiconductor body;
c. applying a liquid to a first zone of the topographically textured semiconductor surface of the semiconductor body, which liquid migrates within the first zone due at least in part to the surface texture of the topographically textured semiconductor surface, and which liquid remains excluded from a second zone of the topographically textured semiconductor surface that is contiguous with the first zone, the exclusion arising due, at least in part, to the surface topographical texture; and
d. allowing a reaction to occur in one of the first zone and the second zone of the semiconductor surface of the semiconductor body, but not both simultaneously.
2. The method of claim 1 , further comprising the step of applying a metal coating to the topographically textured semiconductor surface of the semiconductor body, capable of conducting electric power to an electronic system.
3. The method of claim 1 , further wherein the liquid migrates within the first zone due primarily to the influence of capillary attraction.
4. The method of claim 1 , wherein the liquid comprises a reactive liquid and a chemical reaction occurs in the first zone.
5. The method of claim 4 , further comprising the step of creating a chemically modified volume of material comprising an electronic contact with the semiconductor body, within the first zone due to the chemical reaction.
6. The method of claim 3 , further wherein the first zone bears texture that enables the capillary influence.
7. The method of claim 4 , further wherein the chemical reaction forms a metallic coating within the first zone.
8. The method of claim 4 , further wherein the chemical reaction is a catalyzing reaction with a catalyst that specifically enables the formation of a metallic film by electroless plating within the first zones.
9. The method of claim 4 , further wherein the chemical reaction forms a metallic coating by electroless plating within the first zone.
10. The method of claim 4 , further wherein the chemical reaction forms a metallic coating within the first zone using an organometallic material.
11. The method of claim 3 , further comprising the step of treating the topographically textured surface of the semiconductor body with a material that enhances the flow of liquid under the influence of capillary attraction.
12. The method of claim 1 , the semiconductor body being selected from the group consisting of: silicon, germanium and gallium arsenide.
13. The method of claim 1 , the first zone of the topographically textured surface of the semiconductor body comprising at least one channel having a first and a second portion.
14. The method of claim 1 , the semiconductor surface comprising the surface of a semiconductor wafer.
15. The method of claim 1 , the topographically textured semiconductor surface of a semiconductor body comprising a thin semiconductor film supported by a textured substrate.
16. The method of claim 1 , the semiconductor surface comprising a thin semiconductor film supported by a textured superstrate.
17. The method of claim 1 , wherein the liquid comprises a blocking material and a chemical reaction takes place in the second zone.
18. The method of claim 17 , further wherein the blocking material hardens after it migrates.
19. The method of claim 17 , further comprising the steps of:
a. applying an active, second liquid to the second zone by direct treatment;
b. allowing a chemical reaction to take place in the second zone;
whereby the chemical reaction does not take place in the first zone due to the presence of the blocking material.
20. The method of claim 19 , the second, active liquid being selected from the group consisting of: antireflective coating solvent; electroless plating catalyst; electroless plating chemistry; and electroplating chemistry.
21. The method of claim 19 , the second, active liquid comprising a plurality of liquids, comprising:
a. antireflective coating solvent;
b. electroless plating catalyst;
c. electroless plating chemistry and
d. electroplating chemistry.