Electrical contacts
View Patent ↗Certain embodiments are directed to methods, devices and systems designed to remove selected portions of a material to expose an underlying material or substrate. One or more electrical components may be coupled to the underlying substrate through an electrical contact. Kits and systems for producing electrical contacts are also provided.
1. A method of producing a photovoltaic cell, comprising:
disposing a silicon nitride layer on at least a portion of a silicon substrate;
selectively printing a printable ink comprising an effective amount of a basic material dispersed in a fluid onto a portion of the silicon nitride layer;
exposing the portion of the silicon nitride layer to the effective amount of basic material;
heating the silicon nitride layer and the printed ink at a temperature of about 250° C. to about 300° C. to remove the portion of the silicon nitride layer with the basic material to expose some underlying portion of the silicon substrate without using a mask on the silicon nitride layer; and
electrically coupling at least one electrical component to the exposed silicon substrate to produce the photovoltaic cell.
2. The method of claim 1 , wherein electrically coupling at least one electrical component to the exposed silicon substrate comprises disposing a metal contact on the exposed silicon substrate.
3. The method of claim 2 , further comprising configuring the metal contact to include silver, gold, or mixtures thereof.
4. The method of claim 1 , in which the exposing step comprises heating the basic material to a temperature effective to dissolve the silicon nitride layer to provide a residue on the silicon substrate.
5. The method of claim 1 , in which the exposing step comprises heating the basic material to a temperature effective to promote a reaction between the basic material and the silicon nitride layer to provide a residue on the silicon substrate.
6. The method of claim 1 , further comprising preparing the ink comprising the basic material dispersed in a fluid.
7. The method of claim 6 , in which the basic material is sodium hydroxide and the fluid is an isoparaffinic hydrocarbon.
8. The method of claim 6 , in which the printable ink comprises about 5 wt. % to about 10 wt. % sodium hydroxide.
9. The method of claim 1 , wherein the exposing step involves incubation for a duration of between about 30 seconds and 5 minutes.
10. The method of claim 9 , wherein the exposing step involves incubation for a duration of between about 60 seconds and 3 minutes.
11. The method of claim 1 , wherein the ink has a viscosity of between about 10 and 700 centipoise.
12. The method of claim 11 , wherein the ink has a viscosity of between about 10 and 20 centipoise.
13. The method of claim 1 , wherein the exposing step temperature is in a range of about 250° C. to about 270° C.
14. The method of claim 1 , wherein the basic material in the ink has a concentration of greater than about 5 to 10 weight percent.
15. The method of claim 1 , further comprising heating the ink prior to printing.
16. The method of claim 1 , wherein the ink is printed in a selected pattern on the silicon nitride layer.