# US 10,483,415 B2 · Methods to introduce sub-micrometer, symmetry-breaking surface corrugation to silicon substrates to increase light trapping

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- Number: US 10,483,415 B2
- Document ID: US10483415B2
- Status: Granted
- Kind: B2
- Application number: 15/904,296
- Filed: 2018-02-23
- Published: 2018-07-05
- Granted: 2019-11-19
- Earliest claimed: 2013-10-18
- Assignees: Stc.Unm
- Applicants: Stc.Unm
- Inventors: Sang Eon Han; Brittany R. Hoard; Sang M. Han; Swapnadip Ghosh
- Web page: https://patentgrep.com/patent/US10483415B2

## CPC

- H10F 77/703: {of the semiconductor bodies, e.g. textured active layers}
- G02B 1/005: {made of photonic crystals or photonic band gap materials (photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295)}
- H03H 9/10: Mounting in enclosures {(constructional combinations of enclosure with electromechanical and other electronic elements H03H9/0538)}
- H03H 9/145: for networks using surface acoustic waves
- H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)}
- H10F 10/166: the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells
- H10F 71/103: {including only Group IV materials}
- H10F 71/121: {The active layers comprising only Group IV materials}
- 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
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- 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

Provided is a method for fabricating a nanopatterned surface. The method includes forming a mask on a substrate, patterning the substrate to include a plurality of symmetry-breaking surface corrugations, and removing the mask. The mask includes a pattern defined by mask material portions that cover first surface portions of the substrate and a plurality of mask space portions that expose second surface portions of the substrate, wherein the plurality of mask space portions are arranged in a lattice arrangement having a row and column, and the row is not oriented parallel to a [110] direction of the substrate. The patterning the substrate includes anisotropically removing portions of the substrate exposed by the plurality of spaces.

## Claims

### Claim 1

An optoelectronic device, comprising:
a patterned substrate comprising a surface having a plurality of symmetry-breaking surface corrugations, wherein the symmetry-breaking surface corrugations comprise a symmetry selected from at least one of C4, C2v, C2 and C1 wherein the symmetry breaking corrugations comprise a periodicity from 500 nm to 1000 nm in at least two directions; and
at least one layer formed on the patterned substrate.

### Claim 2 (depends on 1)

The optoelectronic device of claim 1, wherein the at least one layer comprises one or more selected from the group consisting of a metal, a polymer, and a semiconductor.

### Claim 3 (depends on 2)

The optoelectronic device of claim 2, wherein the semiconductor comprises one or more selected from the group consisting of an inorganic semiconductor and an organic semiconductor.

### Claim 4 (depends on 3)

The optoelectronic device of claim 3, wherein the inorganic semiconductor comprises amorphous silicon (a-Si).

### Claim 5 (depends on 1)

The optoelectronic device of claim 1, wherein the plurality of symmetry-breaking surface corrugations defines an array of inverted nanopyramids.

### Claim 6 (depends on 5)

The optoelectronic device of claim 5, wherein the surface comprises flat, unetched areas between the inverted nanopyramids.

### Claim 7 (depends on 1)

The optoelectronic device of claim 1, wherein the silicon substrate comprises c-Si.

### Claim 8 (depends on 1)

The optoelectronic device of claim 1, wherein the plurality of symmetry-breaking surface corrugations defines an array of pyramidal protrusions.

### Claim 9 (depends on 1)

The optoelectronic device of claim 1, wherein the plurality symmetry-breaking surface corrugations have C2 symmetry.

### Claim 10 (depends on 1)

The optoelectronic device of claim 1, wherein the at least one layer is conformally disposed on the plurality of symmetry-breaking surface corrugations.

### Claim 11 (depends on 1)

The optoelectronic device of claim 1, wherein the at least one layer comprises a polymer layer, a transparent conducting oxide layer, or an amorphous silicon (a-Si) layer conformally disposed on the plurality of symmetry-breaking surface corrugations.

### Claim 12 (depends on 1)

The optoelectronic device of claim 1, wherein the at least one layer comprises a plurality of layers, the plurality of layers comprising a front contact layer, a back contact layer and an active layer disposed between front and back contact layers.