Inverted metamorphic multijunction solar cells having a permanent supporting substrate

Patent metadata

Field	Value
Publication number	US-11424381-B2
Application number	US-202016897558-A
Country	US
Kind code	B2
Filing date	Jun 10, 2020
Priority date	Mar 10, 2009
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

The present disclosure provides a method of manufacturing a solar cell that includes providing a semiconductor growth substrate; depositing on said growth substrate a sequence of layers of semiconductor material forming a solar cell; applying a metal contact layer over said sequence of layers; affixing the adhesive polyimide surface of a permanent supporting substrate directly over said metal contact layer and permanently bonding it thereto by a thermocompressive technique; and removing the semiconductor growth substrate.

First claim

What is claimed is:

1. A method of manufacturing a solar cell comprising: providing a semiconductor growth substrate;
depositing on said growth substrate a sequence of layers of semiconductor material forming a solar cell, including a first solar subcell deposited on said substrate having a first band gap; a second solar subcell deposited over said first subcell having a second band gap smaller than said first band gap; a grading interlayer deposited over said second subcell composed of InGaAlAs and having a third band gap larger than said second band gap; a third solar subcell deposited over the grading interlayer and having a fourth band gap smaller than said second band gap such that said third subcell is lattice mismatched with respect to said second subcell;
depositing a metal contact layer over said sequence of layers;
affixing an adhesive surface of a permanent supporting substrate directly over said metal contact layer;
permanently bonding the supporting substrate to the metal contact layer by a thermocompressive technique;
removing the growth substrate.

2. A method as defined in claim 1 , further comprising depositing a coating layer composed of a polymer, a polyimide composition, or an epoxy based photoresist material over the metal contact layer by spinning-on, spraying, or brushing.

3. A method as defined in claim 2 , wherein the coating layer has a thickness of 20 to 25 microns.

4. A method as defined in claim 2 , further comprising curing the coating layer.

5. A method as defined in claim 4 , wherein the curing is performed by a soft bake, near UV exposure (350-400 nm), followed by post exposure bake at an annealing temperature of 205 degrees C. so that the coating layer is inert to subsequent chemical and thermal fabrication steps.

6. A method as defined in claim 1 , wherein the metal contact layer comprises a sequence of metal layers Ti/Au/Ag/Au or Ti/Pd/Ag.

7. A method as defined in claim 1 , wherein the metal contact layer is specularly reflective over the wavelength range of incoming light.

8. A method as defined in claim 2 , further comprising depositing a bonding layer over the coating layer.

9. A method as defined in claim 1 , wherein the thermocompressive technique utilizes a press for directly applying pressure and heat.

10. A method as defined in claim 1 , wherein the permanent supporting substrate is a glass substrate, the method further comprising bonding an adhesive polyimide layer to a surface of the support substrate at a curing temperature above 350° C., prior to the supporting substrate being affixed to the metal contact layer.

11. A method as defined in claim 1 , wherein the semiconductor substrate is removed, after the surrogate substrate has been attached, by at least one of grinding, etching, or epitaxial lift-off.

12. A method as defined in claim 1 , further comprising following removal of the semiconductor growth substrate forming grid electrodes on a surface of the layers of semiconductor material to form a top or light-incident surface of the solar cell.

13. A method as defined in claim 12 , further comprising attaching a cover glass over the grid electrodes.

Assignees

• Solaero Tech Corp

Inventors

• Cornfeld Arthur
• Steinfeldt Jeff

Classifications

• Y02E10/544

  Solar cells from Group III-V materials · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H10F77/12485

  comprising nitride compounds, e.g. InGaN · CPC title

• H10F77/1248 Primary

  having three or more elements, e.g. GaAlAs, InGaAs or InGaAsP · CPC title

• H10F77/124

  comprising only Group III-V materials, e.g. GaAs · CPC title