Fabrication of antireflective Si C surface using plasma
Fabrication of antireflective Si. C 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 Ap. S, Diplomvej 373, DK-2800 Kgs. Lyngby, Denmark yiyu. ou@lightextraction. com Characterization and results Introduction Merits of Si. C as substrate in LEDs : 3 nm 5 nm 7 nm 9 nm 11 nm 13 nm • Small lattice mismatch with Ga. N (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 6 H-Si. C (n=2. 68) Method to enhance the light extraction: • Fabrication of antireflective structures (ARS) on Si. C substrate Fabrication process (a) Thin metal film deposition; (b) Rapid thermal processing; (c) Reactive-ion etching 3 nm 200 nm 5 nm 200 nm 7 nm 200 nm Nano-islands size distribution Au thickness Particle density Mean effective Structure diameter (nm) height (nm) (/μm 2) 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 • Surface reflectance and transmittance were measured in a spectral range from 350 -785 nm by using an integrating sphere • Lower reflectance and higher transmittance are observed after introducing Si. C ARS Summary 9 nm 1µm 11 nm 1µm 13 nm 1µm • Density and average size of ARS can be controlled by tuning the deposited Au film thickness and thermal processing conditions SEM: Au nano-islands (made from different Au film thickness) 3 nm 9 nm 200 nm 5 nm 11 nm 200 nm 7 nm 13 nm • Pseudo-periodic ARS have been fabricated on Si. C substrate by using self-assembled nanopattern 200 nm • 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 SEM: Si. C ARS (made from different Au film thickness) Y. Ou, et al. , Opt. Lett. 37, 3816, 2012. Y. Ou, et al. , Opt. Mater. Express 3, 86, 2013.
- Slides: 1