Fabrication of antireflective SiC surface using plasma etching with self-assembled nanopattern
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Fabrication of antireflective SiC surface using plasma etching with self-assembled nanopattern Y. Ou 1,2 , A. Argyraki 1 , and H. Ou 1 1. DTU Fotonik, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark 2. Light Extraction ApS, Diplomvej 373, DK-2800 Kgs. Lyngby, Denmark [email protected] Introduction Characterization and results Summary • Pseudo-periodic ARS have been fabricated on SiC substrate by using self-assembled nanopattern • Density and average size of ARS can be controlled by tuning the deposited Au film thickness and thermal processing conditions • Suppressed surface reflectance and enhanced light transmittance can be obtained by fabricating ARS with various size • This method is time-efficient, low cost, and scalable Reference Y. Ou, et al., Opt. Lett. 37, 3816, 2012. Y. Ou, et al., Opt. Mater. Express 3, 86, 2013. Nano-islands size distribution Au thickness (nm) Particle density (/μm 2 ) Mean effective diameter (nm) Structure height (nm) 3 1910 15.5 83-245 5 200 42.2 133-262 7 88.9 63 156-315 9 19 125 162-531 11 4.32 231 214-782 13 1.73 319 494-1040 Fabrication process (a) Thin metal film deposition; (b) Rapid thermal processing; (c) Reactive- ion etching SEM: Au nano-islands (made from different Au film thickness) SEM: SiC ARS (made from different Au film thickness) 200nm 3 nm 5 nm 200nm 7 nm 200nm 9 nm 1µm 11 nm 1µm 13 nm 1µm 200nm 3 nm 200nm 5 nm 200nm 7 nm 200nm 9 nm 200nm 11 nm 200nm 13 nm 3 nm 5 nm 7 nm 9 nm 11 nm 13 nm • Surface reflectance and transmittance were measured in a spectral range from 350-785nm by using an integrating sphere • Lower reflectance and higher transmittance are observed after introducing SiC ARS Merits of SiC as substrate in LEDs : •Small lattice mismatch with GaN (3.5%) •Can be conductive which allows for a fabrication of vertical device structure •Excellent thermal conductivity, preferred in high power LEDs Challenge: •Low light extraction efficiency and large internal reflection loss due to high refractive index value of 6H-SiC (n=2.68) Method to enhance the light extraction: •Fabrication of antireflective structures (ARS) on SiC substrate
description
Fabrication of antireflective SiC surface using plasma etching with self-assembled nanopattern. Y. Ou 1,2 , A. Argyraki 1 , and H. Ou 1 1. DTU Fotonik, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark 2. Light Extraction ApS, Diplomvej 373, DK-2800 Kgs. Lyngby, Denmark - PowerPoint PPT Presentation
Transcript of Fabrication of antireflective SiC surface using plasma etching with self-assembled nanopattern
Fabrication of antireflective SiC surface using plasma etching with self-assembled nanopattern
Fabrication of antireflective SiC surface using plasma etching with self-assembled nanopattern
Y. Ou1,2, A. Argyraki1, and H. Ou1
1. DTU Fotonik, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark 2. Light Extraction ApS, Diplomvej 373, DK-2800 Kgs. Lyngby, Denmark
Introduction Characterization and results
Summary
• Pseudo-periodic ARS have been fabricated on SiC substrate by using self-assembled nanopattern
• Density and average size of ARS can be controlled by tuning the deposited Au film thickness and thermal processing conditions
• Suppressed surface reflectance and enhanced light transmittance can be obtained by fabricating ARS with various size
• This method is time-efficient, low cost, and scalable
Reference
Y. Ou, et al., Opt. Lett. 37, 3816, 2012.Y. Ou, et al., Opt. Mater. Express 3, 86, 2013.
Nano-islands size distribution
Au thickness (nm)
Particle density (/μm2)
Mean effective diameter (nm)
Structure height (nm)
3 1910 15.5 83-2455 200 42.2 133-2627 88.9 63 156-3159 19 125 162-531
11 4.32 231 214-78213 1.73 319 494-1040Fabrication process
(a) Thin metal film deposition; (b) Rapid thermal processing; (c) Reactive-ion etching
SEM: Au nano-islands(made from different Au film thickness)
SEM: SiC ARS (made from different Au film thickness)
200nm3 nm 5 nm 200nm 7 nm 200nm
9 nm 1µm 11 nm 1µm 13 nm 1µm
200nm3 nm 200nm5 nm 200nm7 nm
200nm9 nm 200nm11 nm 200nm13 nm
3 nm 5 nm 7 nm
9 nm 11 nm 13 nm
• Surface reflectance and transmittance were measured in a spectral range from 350-785nm by using an integrating sphere
• Lower reflectance and higher transmittance are observed after introducing SiC ARS
Merits of SiC as substrate in LEDs :
•Small lattice mismatch with GaN (3.5%)
•Can be conductive which allows for a fabrication of vertical device structure
•Excellent thermal conductivity, preferred in high power LEDs
Challenge:
•Low light extraction efficiency and large internal reflection loss due to high refractive index value of 6H-SiC (n=2.68)
Method to enhance the light extraction:
•Fabrication of antireflective structures (ARS) on SiC substrate
