Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials

Hao Chen, Qi Zhang, Stephen Y. Chou

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing.

Original languageEnglish (US)
Article number085302
JournalNanotechnology
Volume26
Issue number8
DOIs
StatePublished - Feb 27 2015

Fingerprint

Plasma etching
Aluminum Oxide
Inductively coupled plasma
Sapphire
Etching
Nanostructures
Masks
Substrates
Light emitting diodes
Chlorine
Aspect ratio
Erosion
Gases

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

Cite this

@article{9e65338029ad4022bbe8a54645042670,
title = "Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials",
abstract = "Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing.",
author = "Hao Chen and Qi Zhang and Chou, {Stephen Y.}",
year = "2015",
month = "2",
day = "27",
doi = "10.1088/0957-4484/26/8/085302",
language = "English (US)",
volume = "26",
journal = "Nanotechnology",
issn = "0957-4484",
publisher = "IOP Publishing Ltd.",
number = "8",

}

Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials. / Chen, Hao; Zhang, Qi; Chou, Stephen Y.

In: Nanotechnology, Vol. 26, No. 8, 085302, 27.02.2015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials

AU - Chen, Hao

AU - Zhang, Qi

AU - Chou, Stephen Y.

PY - 2015/2/27

Y1 - 2015/2/27

N2 - Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing.

AB - Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing.

UR - http://www.scopus.com/inward/record.url?scp=84922311055&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84922311055&partnerID=8YFLogxK

U2 - 10.1088/0957-4484/26/8/085302

DO - 10.1088/0957-4484/26/8/085302

M3 - Article

VL - 26

JO - Nanotechnology

JF - Nanotechnology

SN - 0957-4484

IS - 8

M1 - 085302

ER -