Sub‐Micron Anisotropic InP‐based III–V Semiconductor Material Deep Etching for On‐Chip Laser Photonics Devices

Abstract

Two InP-based III-V semiconductor etching recipes are presented for fabrication of on-chip laser photonic devices. Using inductively coupled plasma system with a methane free gas chemistry of chlorine and nitrogen at a high substrate temperature of 250 C, high aspect ratio, anisotropic InP-based nano-structures are etched. Scanning electron microscopy images show vertical sidewall profile of 90 AE 3 , with aspect ratio as high as 10. Atomic Force microscopy measures a smooth sidewall roughness root-mean-square of 2.60 nm over a 3 Â 3 μm scan area. The smallest feature size etched in this work is a nano-ring with inner diameter of 240 nm. The etching recipe and critical factors such as chamber pressure and the carrier plate effect are discussed. The second recipe is of low temperature (À10 C) using Cl 2 and BCl 3 chemistry. This recipe is useful for etching large areas of III-V to reveal the underlying substrate. The availability of these two recipes has created a flexible III-V etching platform for fabrication of on-chip laser photonic devices. As an application example, anisotropic InP-based waveguides of 3 μm width are fabricated using the Cl 2 and N 2 etch recipe and waveguide loss of 4.5 dB mm À1 is obtained.

Integrated Lasers on Silicon at Communication Wavelength: A Progress Review

“…[ 49 ] The rest of the III–V stack layer (InP‐based) can be removed by dry etching. Different recipes have been developed for dry etching of InP‐based layers, mainly methane (CH 4 )‐based [ 69,70 ] and chlorine (Cl 2 )‐based [ 71–73 ] chemistries. In the etching of the InP‐based layers, sidewall roughness needs to be considered as it will affect propagation loss with increased loss due to light scattering from rough sidewalls.…”

“…Ng et al. [ 71 ] has reported etching using Cl 2 ‐based chemistry which gives a sidewall roughness of 2.6 nm. More recently, etching of InP/InGaAsP heterostructures using low‐temperature Cl 2 ‐based chemistries has been reported.…”