US 11,808,998 B2
Optical coupling apparatus and methods of making same
Chan-Hong Chern, Hsin-Chu (TW); and Min-Hsiang Hsu, Hsin-Chu (TW)
Assigned to Taiwan Semiconductor Manufacturing Co., Ltd., Hsin-Chu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsin-Chu (TW)
Filed on Dec. 14, 2022, as Appl. No. 18/081,525.
Application 18/081,525 is a division of application No. 17/186,661, filed on Feb. 26, 2021, granted, now 11,531,173.
Prior Publication US 2023/0121421 A1, Apr. 20, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 6/42 (2006.01)
CPC G02B 6/4215 (2013.01) [G02B 6/4206 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for forming an optical coupler, comprising:
forming an insulation layer on a semiconductor substrate;
epitaxially growing a semiconductor material on the insulation layer to form a semiconductor layer;
etching the semiconductor layer to form an array of etched regions in the semiconductor layer according to a predetermined pattern; and
depositing a dielectric material into the array of etched regions to form an array of scattering elements in the semiconductor layer, wherein the scattering elements are arranged at a plurality of intersections of a first set of concentric elliptical curves crossing with a second set of concentric elliptical curves rotated proximately 90 degrees to form a two-dimensional (2D) grating, wherein
each scattering element is a pillar in a corresponding one of the etched regions, and
the pillar has a top surface whose shape is a concave polygon having at least 8 edges.