HBr based inductively coupled plasma etching of high aspect ratio nanoscale trenches in InP: Considerations for photonic applications

Abstract

Articles you may be interested inFabrication of high-aspect-ratio double-slot photonic crystal waveguide in InP heterostructure by inductively coupled plasma etching using ultra-low pressure AIP Advances 3, 022122 (2013); 10.1063/1.4793082Effect of Cl2-and HBr-based inductively coupled plasma etching on InP surface composition analyzed using in situ x-ray photoelectron spectroscopy Pure HBr based inductively coupled plasma vertical, anisotropic etching provides high aspect ratio ͑20-40͒ nanoscale trenches in InP at 165°C processing temperatures. Since these temperatures are comparatively lower than chlorine based chemistries, HBr should yield improved device reliability. In addition to temperature dependence, other important considerations for integrated photonic applications are discussed. The phenomenon of aspect ratio dependent etching, or reactive ion etching lag, begins to manifest itself when the etch aspect ratio of InP approaches 30:1. No microloading effect is observed in the 100 nm scale trench etching. Physical etch dominates the etching mechanism in this regime, and acceptably smooth, 20 nm rms surface roughness is observed.

Dynamics of extremely anisotropic etching of InP nanowires by HCl

“…The axial etch rate is about a factor 100 more rapid than the radial etch rate with a high anisotropy as compared to other means of etching [18]. This may suggest that there is a kinetic limitation to the process.…”

Recent Advances in Reactive Ion Etching and Applications of High-Aspect-Ratio Microfabrication

“…The temperature of the substrate was 165 C. This high temperature is needed for the In reaction by-products to be sufficiently volatile. A 20 nm etched surface roughness was reported using this etch process [ 117 ].…”

Etching for Vertical Sidewall Formation in TiO2 Nanorods

“…To increase the sidewall angle of the etched TiO 2 structures more vertically, we added hydrogen bromide (HBr) to the Ar/BCl 3 combination and investigated its effect on vertical sidewall formation. Generally, HBr has been studied to make the etched profile more anisotropic than a chlorine-based gas [13][14][15]. It has often been used to form deep Si trenches and obtain etching profiles with high aspect ratios in the compound semiconductor industry.…”