Method to form a photovoltaic cell comprising a thin lamina

• US 8,481,845 B2
• Filed: 02/05/2008
• Issued: 07/09/2013
• Est. Priority Date: 02/05/2008
• Status: Expired due to Fees

• Current Assignee: Neutron Therapeutics Inc.
• Original Assignee: GTAT Corporation (ON Semiconductor Corporation)
• Inventors: Sivaram, Srinivasan, Agarwal, Aditya, Herner, S. Brad, Petti, Christopher J.
• Primary Examiner(s): Johnson, Jonathan
• Assistant Examiner(s): Ayad, Tamir
• Application Number:
  US12/026,530
• Publication Number:
  US 20090194162A1
• Time in Patent Office: 1,981 Days
• Field of Search: 427/74, 136/244, 136/249, 136/256, 438/57
• US Class Current: 136/256
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/0682 back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
• CPC Class Codes: H01L 31/0747 comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/1892 methods involving the use of temporary, removable substrates
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials
• CPC Class Codes: Y02E 10/545 Microcrystalline silicon PV cells
• CPC Class Codes: Y02E 10/546 Polycrystalline silicon PV cells
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Claims

1. A photovoltaic cell comprising:

a monocrystalline semiconductor silicon lamina having a first surface and a second surface opposite the first, the lamina having a thickness between about 1 micron and about 20 microns between the first and second surfaces;

a dielectric layer in contact with the first surface; and

a metal layer in contact with the dielectric layer, the metal layer contacting the first surface through vias formed through the dielectric layer,

wherein the dielectric layer is disposed between the lamina and the metal layer, and the metal layer is disposed between the dielectric layer and a rear support substrate providing support to the lamina,

wherein the metal layer is continuous between all the vias, and wherein the photovoltaic cell comprises the lamina.

2. The photovoltaic cell of claim 1 wherein the dielectric layer comprises silicon nitride or silicon dioxide.

3. The photovoltaic cell of claim 1 wherein the metal layer comprises aluminum.

4. The photovoltaic cell of claim 1 further comprising an antireflective coating in contact with the second surface.

5. The photovoltaic cell of claim 1 wherein the monocrystalline crystalline silicon lamina has a thickness between about 1 micron and about 5 microns.

6. The photovoltaic cell of claim 1 wherein at least portions of the second surface are heavily n-doped or p-doped.

7. The photovoltaic cell of claim 1 wherein the second surface has been roughened.

8. The photovoltaic cell of claim 1 wherein the rear support substrate comprises glass.