# US 9,775,339 B1 · Lateral silicon nanospikes fabricated using metal-assisted chemical etching

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- Number: US 9,775,339 B1
- Document ID: US9775339B1
- Status: Granted
- Kind: B1
- Application number: 15/091,074
- Filed: 2016-04-05
- Published: 2017-10-05
- Granted: 2017-10-03
- Earliest claimed: 2016-04-05
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Stacey M. Gifford; Huan Hu; Pablo Meyer Rojas; Joshua T. Smith
- Web page: https://patentgrep.com/patent/US9775339B1

## CPC

- A01N 25/00: Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application {, e.g. seed treatment or sequential application}; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
- A01N 25/34: Shaped forms, e.g. sheets, not provided for in any other sub-group of this main group
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- H10P 14/60: of insulating materials
- A01N: PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF (preservation of food or foodstuff A23); BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES (preparations for medical, dental or toiletry purposes which kill or prevent the growth or proliferation of unwanted organisms A61K); PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure relates to methods for forming an antimicrobial nanostructure and antimicrobial articles. The methods may include: providing a master template of a layout of the antimicrobial nanostructure on a silicon substrate, depositing a silicon nitride layer on a top surface of the silicon substrate, forming a patterned lithographic resist mask layer on a top surface of the silicon nitride layer, generating certain silicon pillars according to the patterned lithographic resist mask using a resist and reactive ion etching, forming certain lateral silicon nanospikes on the silicon pillars by performing metal assisted chemical etching (MacEtch), and removing the silicon nitride layer and bonding a top cover glass on the silicon pillars to form the antimicrobial nanostructure having lateral silicon nanospikes. The antimicrobial article may include a component of an electronic device, a biomedical article, a household product, a food grade article, a transportation component, or a public building component.

## Claims

### Claim 1

A method for forming an antimicrobial nanostructure, comprising:
providing a master template of a layout of the antimicrobial nanostructure on a silicon substrate;
depositing a silicon nitride layer on a top surface of the silicon substrate;
forming a patterned lithographic resist mask layer on a top surface of the silicon nitride layer;
generating a plurality of silicon pillars according to the patterned lithographic resist mask;
forming a plurality of lateral silicon nanospikes on the plurality of silicon pillars; and
removing the silicon nitride layer and bonding a top cover glass on the plurality of silicon pillars to form the antimicrobial nanostructure.

### Claim 2 (depends on 1)

The method of claim 1, wherein each one of the plurality of silicon pillars comprises a tubular shape having a first end connected to the silicon substrate, and a second end extending away from the silicon substrate, a diameter of each of the plurality of silicon pillars in the range from about 50 nanometers to about 200 nanometers, and ranges therebetween, and a density in the range from about 10 to about 100 per square micron, and ranges therebetween.

### Claim 3 (depends on 1)

The method of claim 1, wherein each one of the plurality of lateral silicon nanospikes comprises a first end connected to a corresponding silicon pillar, and a second end extending away from the corresponding silicon pillar, each one of the nanospikes having a second end diameter in the range from about 1 nanometer to about 10 nanometers, and ranges therebetween, a height in the range of from about 5 nanometers to about 50 manometers, and ranges therebetween, and a density in the range from about 100 to about 500 per square microns, and ranges therebetween.

### Claim 4 (depends on 1)

The method of claim 1, wherein the generating a plurality of silicon pillars according to the patterned lithographic resist mask comprises using a resist and reactive ion etching (ME), wherein a temperature of the ME is in the range of from about −10° C. to about 40° C., and ranges therebetween.

### Claim 5 (depends on 4)

The method of claim 4, wherein a temperature of the RIE is in the range of from about 20° C. to about 30° C., and ranges therebetween.

### Claim 6 (depends on 1)

The method of claim 1, wherein the forming a plurality of lateral silicon nanospikes on the plurality of silicon pillars comprises performing metal assisted chemical etching (MacEtch), wherein a time of the MacEtch is in the range of from about 2 minutes to about 20 minutes, and ranges therebetween, and a temperature of the MacEtch is in the range of from about −10° C. to about 40° C., and ranges therebetween.

### Claim 7 (depends on 1)

The method of claim 1, wherein the silicon substrate comprises a monocrystalline silicon.

### Claim 8 (depends on 1)

The method of claim 1, wherein the top cover glass has a thickness in the range of from about 50 nanometers to about 500 nanometers, and ranges therebetween.

### Claim 9

A method for forming an antibacterial silicon nanostructure, the method comprising:
providing a master template of a layout of the antibacterial silicon nanostructure on a silicon substrate;
depositing a silicon nitride layer on a top surface of the silicon substrate;
forming a patterned lithographic resist mask layer on a top surface of the silicon nitride layer;
generating a plurality of silicon pillars according to the patterned lithographic resist mask;
forming a plurality of lateral silicon nanospikes on the plurality of silicon pillars; and
removing the silicon nitride layer and bonding a top cover glass on the plurality of silicon pillars to form the antibacterial silicon nanostructure.

### Claim 10 (depends on 9)

The method of claim 9, wherein the plurality of silicon pillars comprises a tubular shape having a first end connected to the silicon substrate, and a second end extending away from the silicon substrate, a diameter of each of the plurality of silicon pillars in the range of from about 50 nanometers to about 200 nanometers, and ranges therebetween, and a density in the range of from about 10 to about 100 per square micron, and ranges therebetween.

### Claim 11 (depends on 9)

The method of claim 9, wherein the plurality of lateral silicon nanospikes comprises a first end connected to a corresponding silicon pillar, and a second end extending away from the corresponding silicon pillar, the nanospikes having a second end diameter in the range of from about 1 nanometer to about 10 nanometers, and ranges therebetween, a height in the range of from about 5 nanometer to about 50 nanometer, and ranges therebetween, and a density in the range of from about 100 to about 500 per square micron, and ranges therebetween.

### Claim 12 (depends on 9)

The method of claim 9, wherein the generating a plurality of silicon pillars according to the patterned lithographic resist mask comprises using a resist and reactive ion etching (ME), wherein a temperature of the ME is in the range of from about −10° C. to about 40° C., and ranges therebetween.

### Claim 13 (depends on 9)

The method of claim 9, wherein the forming a plurality of lateral silicon nanospikes on the plurality of silicon pillars comprises performing metal assisted chemical etching (MacEtch), wherein a time of the MacEtch is in the range of from about 2 minutes to about 20 minutes, and ranges therebetween, and a temperature of the MacEtch is in the range of from about −10° C. to about 40° C., and ranges therebetween.

### Claim 14 (depends on 13)

The method of claim 13, wherein a temperature of the MacEtch is in the range of from about 20° C. to about 30° C., and ranges therebetween.

### Claim 15 (depends on 9)

The method of claim 9, wherein the silicon substrate comprises a monocrystalline silicon.

### Claim 16 (depends on 9)

The method of claim 9, wherein the top cover glass has a thickness in the range of from about 50 nanometers to about 500 nanometers, and ranges therebetween.