# US 9,520,507 B2 · Solar cells with improved lifetime, passivation and/or efficiency

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,520,507 B2
- Document ID: US9520507B2
- Status: Granted
- Kind: B2
- Application number: 14/579,935
- Filed: 2014-12-22
- Published: 2016-06-23
- Granted: 2016-12-13
- Earliest claimed: 2014-12-22
- Assignees: SunPower Corporation
- Applicants: David D. Smith; Tim Dennis; Russelle De Jesus Tabajonda
- Inventors: David D. Smith; Tim Dennis; Russelle De Jesus Tabajonda
- Web page: https://patentgrep.com/patent/US9520507B2

## CPC

- H10F 77/935: {for photovoltaic devices or modules}
- H10F 10/14: Photovoltaic cells having only PN homojunction potential barriers
- H10F 10/165: the heterojunctions being Group IV-IV heterojunctions, e.g. Si/Ge, SiGe/Si or Si/SiC photovoltaic cells
- H10F 10/166: the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells
- H10F 71/121: {The active layers comprising only Group IV materials}
- H10F 71/128: {Annealing}
- H10F 71/129: {Passivating}
- H10F 71/131: {Recrystallisation; Crystallization of amorphous or microcrystalline semiconductors}
- H10F 71/132: {Gettering}
- H10F 77/164: Polycrystalline semiconductors
- H10F 77/1642: {including only Group IV materials}
- H10F 77/219: {Arrangements for electrodes of back-contact photovoltaic cells}
- H10F 77/311: {for photovoltaic cells}
- H10P 36/03: {within silicon bodies}
- H10F 71/00: Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- Y02E 10/546: Polycrystalline silicon PV cells
- Y02E 10/547: Monocrystalline silicon PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method of fabricating a solar cell can include forming a dielectric region on a silicon substrate. The method can also include forming an emitter region over the dielectric region and forming a dopant region on a surface of the silicon substrate. In an embodiment, the method can include heating the silicon substrate at a temperature above 900 degrees Celsius to getter impurities to the emitter region and drive dopants from the dopant region to a portion of the silicon substrate.

## Claims

### Claim 1

A solar cell, the solar cell, having a front side which faces the sun during normal operation and a back side opposite the front side, the solar cell comprising:
a dielectric region over a silicon substrate, wherein a portion of the silicon substrate has a dopant concentration of approximately less than or equal to 20×1018 cm−3;
a first emitter region having metal impurities formed over the dielectric region; and
a first metal contact formed over the first emitter region;
a second emitter region having metal impurities formed over the dielectric region, wherein the second emitter region is formed at least partially over the first emitter region, and wherein the first and second emitter regions are formed on a same side of the solar cell: and
a second metal contact formed over the second emitter region.

### Claim 2 (depends on 1)

The solar cell of claim 1, wherein the first emitter region and the first metal contact are formed on the hack side of the solar cell.

### Claim 3 (depends on 1)

The solar cell of claim 1, wherein the first emitter region and the first metal contact are formed on the front side of the solar cell.

### Claim 4 (depends on 1)

The solar cell of claim 1, wherein the portion of the silicon substrate having a dopant concentration of approximately less than or equal to 20×1018 cm−3 is on the front side of the solar cell.

### Claim 5 (depends on 1)

The solar cell of claim 1, wherein the first emitter region, is a doped polysilicon region.