Patent ID: 8580668
Filing Date: 2013-11-12
Classification: H01L

Abstract:
1. A method of manufacturing an ohmic contact layer which is used for a light emitting device, the method comprising: forming a first conductive material layer on a semiconductor layer; forming a mask layer comprising a plurality of nano-sized islands on the first conductive material layer to contact with the first conductive material layer; forming a second conductive material layer on the first conductive material layer and on the islands in the mask layer; removing the portion of the second conductive material on the islands through a lift-off process using a solvent such that the second conductive material layer has a plurality of nano-sized through-holes corresponding to the nano-sized islands; and forming a conductive pad on a part of the surface of the second conductive material layer having a plurality of nano-sized through-holes, the second conductive material layer being exposed to the outside, wherein the first and second conductive material layers are formed of an identical transparent conductive material and form a layer, and whereby the layer comprising the first and second conductive layers is provided as the ohmic contact layer, wherein a plurality of nano-sized islands have a pitch of A and satisfy A=m×λ/4×n (m: integer, λ: wavelength of the light emitting device, n: refractive index of the first and second conductive material layers), wherein the forming of the mask layer comprises: coating a photoresist on the first conductive material layer; exposing the photoresist with a first laser and second laser to form a latent image corresponding to the islands in the photoresist, the exposing of the photoresist being performed through laser holography using laser interference, wherein the first laser is directly radiated onto the photoresist and the second laser is indirectly radiated thereunto through a reflector such that an interference pattern is formed; and forming the islands on the first conductive material layer by developing the photoresist using a solvent, wherein the exposing the photoresist with the first laser and second laser comprises: exposing the photoresist with the first laser; rotating a structure which comprises the semiconductor layer, the first conductive material layer formed on the semiconductor layer, and the photoresist formed on the first conductive material layer; and after rotating the structure, exposing the photoresist with the second layer.