Fabrication of Two-Depth Apodized Grating by Selective Etching of InP in CH4/H2 Reactive Ion Etching

Abstract

We fabricated the basic structure of an apodized grating with two depths of 120 and 200 nm for InP in one etching process during reactive ion etching (RIE) with methane and hydrogen. In the process, we first performed selective RIE, in which InP windows of the grating were etched in a region with a thick layer but not etched with polymer deposition in a region without the thick layer. Next, we performed oxygen plasma exposure to remove the polymer and a second RIE for the windows of the gratings both with and without the thick layers.