Highly selective dry etching of GaP in the presence of Al_xGa_1–xP with a SiCl₄/SF₆plasma

Abstract

We present an inductively coupled-plasma reactive-ion etching process that simultaneously provides both a high etch rate and unprecedented selectivity for gallium phosphide (GaP) in the presence of aluminum gallium phosphide (Al x Ga1−xP). Utilizing mixtures of silicon tetrachloride (SiCl 4 ) and sulfur hexafluoride (SF 6 ), selectivities exceeding 2700:1 are achieved at GaP etch rates above 3000 nm min −1 . A design of experiments has been employed to investigate the influence of the inductively coupled-plasma power, the chamber pressure, the DC bias and the ratio of SiCl 4 to SF 6 . The process enables the use of thin Al x Ga1−xP stop layers even at aluminum contents of a few percent.

Optomechanics with one-dimensional gallium phosphide photonic crystal cavities

“…Briefly, an epitaxial GaP/AlxGa1-xP/GaP heterostructure is grown by metal-organic chemical vapor deposition on a [100]-oriented GaP wafer, which is subsequently bonded to an oxidized silicon wafer. The original GaP growth wafer is first thinned by lapping and then dry etched with SiCl4 and SF6 in a process that selectively removes GaP in the presence of AlxGa1-xP [32]. The AlxGa1-xP etch-stop layer is removed selectively with concentrated HCl, yielding the desired GaPoI substrate.…”

Integrated gallium phosphide nonlinear photonics

“…The growth wafer is then directly bonded to a Si wafer with a 2 µm thermal oxide, after depositing a thin (5 nm) layer of Al2O3 on both surfaces. To remove the growth substrate, we use a combination of wet etching and a rapid, highly selective dry etch based on inductively-coupled plasma reactive ion etching (ICP-RIE) with SiCl4 and SF6 [30]. The AlGaP layer is then removed with concentrated HCl, leaving the GaP device layer exposed for processing.…”

Nanoscopic charge fluctuations in a gallium phosphide waveguide measured by single molecules

“…Semiconductors such as Si and GaAs offer considerably larger n but at the expense of strong absorption for wavelengths smaller than 800 nm. Gallium phosophide (GaP) presents a very attractive alternative with n > ∼ 3 and a cutoff wavelength below 600 nm [18][19][20][21], and indeed, recent efforts have established fabrication of high-quality nanophotonic chips from this material on SiO 2 [22,23]. In this work, we show efficient coupling of single organic molecules to a GaP nanoguide.…”

“…Efficient coupling of molecules to a GaP nanoguide. The core of our experimental platform is a 50 µm long GaP nanoguide fabricated on a 2 µm thick SiO 2 layer on a silicon substrate [22,23]. The nanoguide has a crosssection of 100 nm × 160 nm, is terminated on both sides by grating couplers and is decorated by sawtooth-shaped gold microelectrodes placed 2 µm from the nanoguide (see Fig.…”

“…1(b)). Fabrication details are presented in earlier works [21][22][23]. The nanostructures are covered by a para-dichlorobenzene (pDCB) crystal confined in a nanochannel as described in previous publications [11,17,24].…”