# US 2014/0151706 A1 · Structures incorporating silicon nanoparticle inks, densified silicon materials from nanoparticle silicon deposits and corresponding methods

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

- Number: US 2014/0151706 A1
- Document ID: US20140151706A1
- Status: Published application
- Kind: A1
- Application number: 14/175,561
- Filed: 2014-02-07
- Published: 2014-06-05
- Earliest claimed: 2011-11-01
- Assignees: NanoGram Corporation
- Applicants: NanoGram Corporation
- Inventors: Guojun Liu; Shivkumar Chiruvolu; Weidong Li; Uma Srinivasan
- Web page: https://patentgrep.com/patent/US20140151706A1

## CPC

- H10D 62/40: Crystalline structures
- 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 71/121: {The active layers comprising only Group IV materials}
- H10F 77/122: comprising only Group IV materials
- H10F 77/1433: {Quantum dots}
- H10P 14/00: Formation of materials, e.g. in the shape of layers or pillars
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/265: {using solutions}
- H10P 14/3411: {Silicon, silicon germanium or germanium}
- H10P 14/3452: {Microstructure}
- H10P 14/3461: {Nanoparticles}
- H10P 32/1414: {the applied layer being silicon, silicide or SIPOS, e.g. polysilicon or porous silicon}
- H10P 32/171: {being group IV material}
- H10P 32/19: {Diffusion sources}
- H10P 72/0436: {mainly by radiation}
- Y02E 10/547: Monocrystalline silicon PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- 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

Silicon nanoparticle inks provide a basis for the formation of desirable materials. Specifically, composites have been formed in thin layers comprising silicon nanoparticles embedded in an amorphous silicon matrix, which can be formed at relatively low temperatures. The composite material can be heated to form a nanocrystalline material having crystals that are non-rod shaped. The nanocrystalline material can have desirable electrical conductive properties, and the materials can be formed with a high dopant level. Also, nanocrystalline silicon pellets can be formed from silicon nanoparticles deposited form an ink in which the pellets can be relatively dense although less dense than bulk silicon. The pellets can be formed from the application of pressure and heat to a silicon nanoparticle layer. The materials described herein can be effectively used for the formation of doped contacts for crystalline silicon solar cells, thin film silicon solar cells, electronic devices, such as printed electronics, and other useful products.

## Claims

### Claim 1

A structure comprising a substrate having a surface and a composite coating on at least a portion of the surface with an average thickness of no more than about 5 microns and comprising crystalline silicon nanoparticles with an average primary particle size of no more than about 100 nm and an amorphous silicon matrix around the crystalline silicon particles.

### Claim 2 (depends on 1)

The structure of claim 1 wherein the coating has a void volume of no more than about 20%.

### Claim 3 (depends on 1)

The structure of claim 1 wherein the thickness of the composite coating is no more than about 3 microns.

### Claim 4 (depends on 1)

The structure of claim 1 further comprises a top coat of amorphous silicon on the composite coating, the top coat having an average thickness no more than about 5 microns.

### Claim 5 (depends on 1)

The structure of claim 1 wherein the crystalline silicon nanoparticles have an average particle size of no more than about 75 nm.

### Claim 6 (depends on 1)

The structure of claim 1 wherein the crystalline silicon nanoparticles comprise a dopant with a concentration of at least about 1×1020 atoms/cm3.

### Claim 7 (depends on 6)

The structure of claim 6 wherein the amorphous silicon is intrinsic.

### Claim 8 (depends on 1)

The structure of claim 1 wherein the composite coating is patterned covering no more than about 75 percent of the substrate surface.

### Claim 9 (depends on 1)

The structure of claim 1 wherein the substrate comprises highly crystalline elemental silicon along the surface.

### Claim 10 (depends on 1)

The structure of claim 1 wherein the crystalline silicon nanoparticles are doped with phosphorous.

### Claim 11 (depends on 1)

The structure of claim 1 wherein the crystalline silicon nanoparticles are doped with boron.

### Claim 12

A method for application of a silicon coating on a substrate, the method comprising:
depositing an amorphous silicon matrix onto and into a particulate coating of crystalline silicon nanoparticles having an average primary particle size of no more than about 200 nm to form a composite with crystalline silicon nanoparticles embedded in an amorphous matrix, wherein the particulate coating has an average thickness of no more than about 5 microns.

### Claim 13 (depends on 12)

The method of claim 12 wherein the application of the amorphous silicon is performed using LP-CVD.

### Claim 14 (depends on 12)

The method of claim 12 wherein the crystalline silicon nanoparticles were deposited using an ink.

### Claim 15 (depends on 12)

The method of claim 12 wherein the resulting coating has a void volume of no more than about 20%.

### Claim 16 (depends on 12)

The method of claim 12 wherein the deposited amorphous coating forms a top coat over a composite of the amorphous elemental silicon and the crystalline silicon nanoparticle and wherein the top coat has an average thickness of no more than about 5 microns.

### Claim 17 (depends on 12)

The method of claim 12 wherein the crystalline silicon nanoparticles are doped and the amorphous elemental silicon is intrinsic.

### Claim 18 (depends on 17)

The method of claim 17 wherein crystalline silicon nanoparticles have a phosphorous dopant or a boron dopant with a dopant concentration from about 0.25 atomic percent to about 15 atomic percent.

### Claim 19 (depends on 12)

The method of claim 12 further comprising annealing the composite comprising heating the composite at a temperature from abut 700° C. to about 1400° C. to form a nanocrystalline material.

### Claim 20 (depends on 19)

The method of claim 19 wherein the nanocrystalline material has a void volume of no more than about 5% and a sheet resistance of no more than about 120 ohms/square.