# US 12,009,449 B2 · Solar cell having an emitter region with wide bandgap semiconductor material

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

- Number: US 12,009,449 B2
- Document ID: US12009449B2
- Status: Granted
- Kind: B2
- Application number: 18/107,917
- Filed: 2023-02-09
- Published: 2023-06-22
- Granted: 2024-06-11
- Earliest claimed: 2012-03-23
- Assignees: Maxeon Solar Pte. Ltd.
- Applicants: Maxeon Solar Pte. Ltd.
- Inventors: Richard M. Swanson; Marius M. Bunea; Michael C. Johnson; David D. Smith; Yu-Chen Shen; Peter J. Cousins; Tim Dennis
- Web page: https://patentgrep.com/patent/US12009449B2

## CPC

- H10F 10/166: the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells
- H10F 10/14: Photovoltaic cells having only PN homojunction potential barriers
- H10F 10/146: {Back-junction photovoltaic cells, e.g. having interdigitated base-emitter regions on the back side}
- H10F 10/16: Photovoltaic cells having only PN heterojunction potential barriers
- H10F 10/165: the heterojunctions being Group IV-IV heterojunctions, e.g. Si/Ge, SiGe/Si or Si/SiC photovoltaic cells
- H10F 71/121: {The active layers comprising only Group IV materials}
- H10F 71/129: {Passivating}
- H10F 77/219: {Arrangements for electrodes of back-contact photovoltaic cells}
- H10F 77/311: {for photovoltaic cells}
- H10F 77/703: {of the semiconductor bodies, e.g. textured active layers}
- 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
- 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

Solar cells having emitter regions composed of wide bandgap semiconductor material are described. In an example, a method includes forming, in a process tool having a controlled atmosphere, a thin dielectric layer on a surface of a semiconductor substrate of the solar cell. The semiconductor substrate has a bandgap. Without removing the semiconductor substrate from the controlled atmosphere of the process tool, a semiconductor layer is formed on the thin dielectric layer. The semiconductor layer has a bandgap at least approximately 0.2 electron Volts (eV) above the bandgap of the semiconductor substrate.

## Claims

### Claim 1

A solar cell, comprising:
a semiconductor substrate;
a first thin dielectric layer disposed on the semiconductor substrate;
a first semiconductor region of a first conductivity type disposed on the first thin dielectric layer;
a second thin dielectric layer disposed on the semiconductor substrate; and
a second semiconductor region of a second conductivity type disposed on the second thin dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second thin dielectric layer is disposed on a sidewall surface of the first semiconductor region, and the second dielectric layer laterally separates the first and second semiconductor regions.

### Claim 2 (depends on 1)

The solar cell of claim 1, wherein the first semiconductor region is a first polysilicon region, and the second semiconductor region is a second polysilicon region.

### Claim 3 (depends on 1)

The solar cell of claim 1, wherein the first thin dielectric layer is a first oxide layer, and the second thin dielectric layer is a second oxide layer.

### Claim 4 (depends on 3)

The solar cell of claim 3, wherein the first oxide layer and the second oxide layer comprise silicon.

### Claim 5 (depends on 1)

The solar cell of claim 1, wherein the second thin dielectric layer covers at least a portion of the first semiconductor region.

### Claim 6 (depends on 1)

The solar cell of claim 1, wherein the second thin dielectric layer and the second semiconductor region include a contact opening through which a metal contact is formed to contact to the first semiconductor region.

### Claim 7 (depends on 1)

The solar cell of claim 1, wherein the first conductivity type is N-type, and the second conductivity type is P-type.

### Claim 8 (depends on 1)

The solar cell of claim 1, wherein the first conductivity type is P-type, and the second conductivity type is N-type.

### Claim 9 (depends on 1)

The solar cell of claim 1, wherein the second semiconductor region has a dopant concentration approximately in the range of 1×1017-1×1021 atoms/cm3.

### Claim 10 (depends on 1)

The solar cell of claim 1, further comprising:
an oxide layer disposed over a light receiving surface of the semiconductor substrate, the light receiving surface opposite the first thin dielectric layer and the second thin dielectric layer;
an amorphous silicon layer disposed on the oxide layer; and
an anti-reflective coating (ARC) layer disposed on the amorphous silicon layer, the ARC layer comprising silicon nitride.

### Claim 11

A solar cell, comprising:
a silicon substrate;
a first dielectric layer on the silicon substrate;
a first silicon region of a first conductivity type on the first dielectric layer;
a second dielectric layer on the silicon substrate; and
a second silicon region of a second conductivity type on the second dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second dielectric layer is on a sidewall surface of the first silicon region, and the second dielectric layer laterally separates the first and second silicon regions.

### Claim 12 (depends on 11)

The solar cell of claim 11, wherein the first silicon region is a first polysilicon region, and the second silicon region is a second polysilicon region.

### Claim 13 (depends on 11)

The solar cell of claim 11, wherein the first dielectric layer is a first oxide layer, and the second dielectric layer is a second oxide layer.

### Claim 14 (depends on 13)

The solar cell of claim 13, wherein the first oxide layer and the second oxide layer comprise silicon.

### Claim 15 (depends on 11)

The solar cell of claim 11, wherein the second dielectric layer covers at least a portion of the first silicon region.

### Claim 16 (depends on 11)

The solar cell of claim 11, wherein the second dielectric layer and the second silicon region include a contact opening through which a metal contact is formed to contact to the first silicon region.

### Claim 17 (depends on 11)

The solar cell of claim 11, wherein the first conductivity type is N-type, and the second conductivity type is P-type.

### Claim 18 (depends on 11)

The solar cell of claim 11, wherein the first conductivity type is P-type, and the second conductivity type is N-type.

### Claim 19 (depends on 11)

The solar cell of claim 11, wherein the second silicon region has a dopant concentration approximately in the range of 1×1017-1×1021 atoms/cm3.

### Claim 20 (depends on 11)

The solar cell of claim 11, further comprising:
an oxide layer over a light receiving surface of the silicon substrate, the light receiving surface opposite the first dielectric layer and the second dielectric layer;
an amorphous silicon layer on the oxide layer; and
an anti-reflective coating (ARC) layer on the amorphous silicon layer, the ARC layer comprising silicon nitride.

### Claim 21

A solar cell, comprising:
a semiconductor substrate;
a first thin dielectric layer disposed on the semiconductor substrate;
a first semiconductor region of a first conductivity type disposed on the first thin dielectric layer;
a second thin dielectric layer disposed on the semiconductor substrate; and
a second semiconductor region of a second conductivity type disposed on the second thin dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second thin dielectric layer is disposed on a lateral surface of the first semiconductor region, and the second dielectric layer separates the first and second semiconductor regions, wherein the second semiconductor region has a dopant concentration approximately in the range of 1×1017-1×1021 atoms/cm3.

### Claim 22

A solar cell, comprising:
a semiconductor substrate;
a first thin dielectric layer disposed on the semiconductor substrate;
a first semiconductor region of a first conductivity type disposed on the first thin dielectric layer;
a second thin dielectric layer disposed on the semiconductor substrate;
a second semiconductor region of a second conductivity type disposed on the second thin dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second thin dielectric layer is disposed on a lateral surface of the first semiconductor region, and the second dielectric layer separates the first and second semiconductor regions;
an oxide layer disposed over a light receiving surface of the semiconductor substrate, the light receiving surface opposite the first thin dielectric layer and the second thin dielectric layer;
an amorphous silicon layer disposed on the oxide layer; and
an anti-reflective coating (ARC) layer disposed on the amorphous silicon layer, the ARC layer comprising silicon nitride.