# US 9,753,006 B2 · High density nano-array for sensing

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- Number: US 9,753,006 B2
- Document ID: US9753006B2
- Status: Granted
- Kind: B2
- Application number: 14/743,637
- Filed: 2015-06-18
- Published: 2016-12-01
- Granted: 2017-09-05
- Earliest claimed: 2015-05-29
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Qing Cao; Kangguo Cheng; Zhengwen Li; Fei Liu; Zhen Zhang
- Web page: https://patentgrep.com/patent/US9753006B2

## CPC

- G01N 27/44791: {Microapparatus (sample containers with integrated microfluidic structures B01L3/5027)}
- G01N 27/4146: {involving nanosized elements, e.g. nanotubes, nanowires}
- G01N 33/48707: {by electrical means (G01N33/49, G01N33/493 take precedence)}
- H10P 14/6308: {of Group IV semiconductors}
- H10P 50/242: {of Group IV materials}
- H10P 50/283: {by chemical means}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A sensor includes a semiconductor substrate having first pointed nodes extending into a channel from a first side of the channel. Second pointed nodes extend into the channel from a second side of the channel, which is opposite the first side. The second pointed nodes being self-aligned to the first pointed nodes on the opposite side of the channel. The first pointed nodes and the second pointed nodes are connected to a circuit to detect particles in the channel.

## Claims

### Claim 1

A method for forming a sensor, comprising:
forming a buried doping layer in a semiconductor substrate;
forming fins in the substrate down to the buried doping layer;
depositing a permeable filler material from the buried doping layer to a height along the fins;
enclosing portions of the fin above the height along the fins in a non-permeable material;
decomposing the fins within the filler material by permeating a reactant through the filler material to form first pointed nodes in the portions of the fins and second pointed nodes in the buried doping layer, the first and second pointed nodes being self-aligned to each other; and
removing the filler material to form a channel for receiving materials to be sensed.

### Claim 2 (depends on 1)

The method as recited in claim 1, further comprising forming components for a detection circuit which connects to the first and second pointed nodes.

### Claim 3 (depends on 2)

The method as recited in claim 2, further comprising detecting particles in the channel by measuring electrical fluctuations in the detection circuit.

### Claim 4 (depends on 1)

The method as recited in claim 1, further comprising lining the channel with a dielectric material.

### Claim 5 (depends on 1)

The method as recited in claim 1, further comprising forming a dummy gate over the fins and non-permeable material, and doping the portions of the fins on opposite sides of the dummy gate to form source and drain regions.

### Claim 6 (depends on 5)

The method as recited in claim 5, further comprising forming contacts to the source and drain regions on opposite sides of the dummy gate and forming a gate contact down to the buried doping layer.

### Claim 7 (depends on 1)

The method as recited in claim 1, further comprising forming trenches to access the channel.

### Claim 8 (depends on 1)

The method as recited in claim 1, wherein forming fins in the substrate includes etching the fins using a sidewall image transfer process.

### Claim 9

A method for forming a sensor, comprising:
forming a buried doping layer in a semiconductor substrate;
etching fins in the substrate down to the buried doping layer;
depositing an oxygen permeable filler material from the buried doping layer to a height along the fins;
enclosing portions of the fin above the height along the fins in a non-permeable nitride material;
oxidizing the fins within the filler material to form self-aligned bird's peak points extending into the filler material from opposite sides; and
removing the filler material to form a channel for receiving materials to be sensed.

### Claim 10 (depends on 9)

The method as recited in claim 9, further comprising forming components for a detection circuit which connect to the self-aligned bird's peak points.

### Claim 11 (depends on 10)

The method as recited in claim 10, further comprising detecting particles in the channel by measuring electrical fluctuations in the detection circuit.

### Claim 12 (depends on 9)

The method as recited in claim 9, further comprising lining the channel with a dielectric material.

### Claim 13 (depends on 9)

The method as recited in claim 9, further comprising:
forming a dummy gate over the fins and non-permeable material, and doping the portions of the fins on opposite sides of the dummy gate to form source and drain regions;
forming contacts to the source and drain regions on opposite sides of the dummy gate; and
forming a gate contact to the buried doping layer.