# US 8,772,630 B2 · Solar cell and method of manufacturing the same

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- Number: US 8,772,630 B2
- Document ID: US8772630B2
- Status: Granted
- Kind: B2
- Application number: 12/588,167
- Filed: 2009-10-06
- Published: 2011-01-06
- Granted: 2014-07-08
- Earliest claimed: 2009-07-06
- Assignees: LG Electronics Inc.
- Applicants: Kyoungsoo Lee; Manhyo Ha; Jonghwan Kim
- Inventors: Kyoungsoo Lee; Manhyo Ha; Jonghwan Kim
- Web page: https://patentgrep.com/patent/US8772630B2

## CPC

- H10F 77/70: Surface textures, e.g. pyramid structures
- H10F 10/14: Photovoltaic cells having only PN homojunction potential barriers
- H10F 71/103: {including only Group IV materials}
- H10F 71/121: {The active layers comprising only Group IV materials}
- H10F 71/131: {Recrystallisation; Crystallization of amorphous or microcrystalline semiconductors}
- H10F 77/1642: {including only Group IV materials}
- H10F 77/1645: {including microcrystalline silicon}
- H10F 77/1662: {including only Group IV materials}
- H10F 77/211: {for photovoltaic cells}
- H10F 77/315: {the coatings being antireflective or having enhancing optical properties}
- H10F 77/703: {of the semiconductor bodies, e.g. textured active layers}
- Y02E 10/52: PV systems with concentrators
- Y02E 10/545: Microcrystalline silicon PV cells
- Y02E 10/546: Polycrystalline silicon PV cells
- Y02E 10/547: Monocrystalline silicon PV cells
- Y02E 10/548: Amorphous 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

The present invention relates to solar cells. Such solar cells include a substrate containing a first impurity of a first conductive type and having a textured surface with a plurality of jagged portions. Such solar cells also have an emitter layer positioned on the textured surface and containing a second impurity of a second conductive type opposite to the first conductive type, a first electrode having a plurality of first metal particles, electrically connected to the emitter layer, and a second electrode electrically connected to the substrate. The diameter of the first metal particles is larger than the peak-to-peak distance between adjacent jagged portions.

## Claims

### Claim 1

A solar cell comprising:
a substrate containing impurities of a first conductive type, the substrate having a textured surface including a plurality of jagged portions;
an emitter layer covering the textured surface, the emitter layer containing impurities of a second conductive type, wherein the conductivity of the second type is opposite the conductivity of the first conductive type, and wherein the emitter layer has a textured surface, over the textured surface of the substrate, including a plurality of jagged portions that generally align with the plurality of jagged portions of the substrate;
a first electrode electrically connected to the emitter layer;
a second electrode electrically connected to the substrate, wherein a concentration of the impurities of the second conductive type within the emitter layer is greatest in a proximity to a peak of each jagged portion, such that a sheet resistance near the peak of each jagged portion is less than that of a remaining portion of each jagged portion,
wherein the first electrode comprises a plurality of first metal particles and a plurality of second metal particles, and each of the plurality of first metal particles is a recrystallized particle of second metal particles,
wherein a diameter of all the plurality of first metal particles is greater than a peak-to-peak distance between adjacent jagged portions of the emitter layer,
wherein a diameter of all the plurality of second metal particles is greater than the diameter of each of the plurality of first metal particles,
wherein first metal particles, and not second metal particles, are in contact with the plurality of jagged portions of the emitter layer,
wherein the diameter of each of the plurality of second metal particles is about 2 μm to about 5 μm.

### Claim 2 (depends on 1)

The solar cell of claim 1, wherein the concentration of the impurities of the second conductive type varies within the emitter layer.

### Claim 3 (depends on 2)

The solar cell of claim 2, wherein a thickness of the emitter layer is proportional to the concentration of the impurities of the second conductive type.

### Claim 4 (depends on 1)

The solar cell of claim 1, wherein a thickness of the emitter layer varies.

### Claim 5 (depends on 4)

The solar cell of claim 4, wherein the thickness of the emitter layer is greatest in the proximity of the peak of each jagged portion.

### Claim 6 (depends on 4)

The solar cell of claim 4, wherein the thicknesses of the emitter layer varies from about 250 nm to 350 nm.

### Claim 7 (depends on 6)

The solar cell of claim 6, wherein the emitter layer has a sheet resistance of about 80 Ω/sq. to 15 Ω/sq.

### Claim 8 (depends on 1)

The solar cell of claim 1, wherein the plurality of first metal particles and the plurality of second metal particles are Ag particles.

### Claim 9 (depends on 1)

The solar cell of claim 1, wherein the diameter of each of the plurality of first metal particles is about 300 nm to 700 nm.

### Claim 10 (depends on 1)

The solar cell of claim 1, wherein the distance between adjacent jagged portions is about 200 nm to 500 nm.

### Claim 11 (depends on 1)

The solar cell of claim 1, wherein the plurality of first metal particles are arranged on the plurality of jagged portions of the emitter layer, and the plurality of second metal particles are arranged on the plurality of first metal particles.

### Claim 12 (depends on 1)

The solar cell of claim 1, wherein the first electrode comprises at least one material selected from nickel (Ni), copper (Cu), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti), gold (Au), and a combination thereof.