Development of InSb dry etch for mid-IR applications
We present a new chlorine-free dry etching process which was used to successfully etch indium antimonide grown on gallium arsenide substrates while keeping the substrate temperature below 150°C. By use of a reflowed photoresist mask a sidewall with 60degree positive slope was achieved, whereas a nearly vertical one was obtained when hard masks were used. Long etch tests demonstrated the non-selectivity of the process by etching through the entire multi-layer epitaxial structure. Electrical and optical measurements on devices fabricated both by wet and dry etch techniques provided similar results, proving that the dry etch process does not cause damage to the material. This technique has a great potential to replace the standard wet etching techniques used for fabrication of indium antimonide devices with a non-damaging low temperature plasma process. Display Omitted Chlorine-free low-temperature dry etch of MBE grown InSb on GaAs60° positive sloped or nearly vertical etch depending on maskNon-selective process etching through Insb, GaSb and GaAsLow damage process with potential to replace standard InSb wet etch
Inductively coupled plasma-reactive ion etching of InSb using CH4∕H2∕Ar plasma
InSb is an important material for optoelectronic devices. Most InSb devices are currently wet etched, and the etching geometries are limited due to the isotropic nature of wet etching. Inductively coupled plasma (ICP)–reactive ion etching (RIE) is a more desirable alternative because it offers a means of producing small anisotropic structures especially needed in large format infrared focal plane arrays. This work describes the novel use of ICP-RIE for fabricating InSb mesas with CH4∕H2∕Ar plasma and presents the influences of the process parameters on the etch rate and surface morphology. The parameters investigated include bias radio frequency power (50–250W), % CH4 in H2 (10–50), argon (Ar) partial pressure (0–0.3Pa with total pressure of 1.0Pa), and total pressure (0.35–4Pa). With the process parameters optimized in this investigated ranges, good etching results have been achieved with etch rates up to 80nm∕min, and etch features with sidewall angles of about 80°, the etched surface is as smooth as be...
Electron Cyclotron Resonance-Reactive Ion Beam Etching of InP by Cyclic Injection of CH4/H2/Ar and O2
Electron cyclotron resonance-reactive ion beam etching (ECR-RIBE) is very useful for fabricating semiconductor photonic devices and integrated circuits (PICs). The mixture gas of CH4/H2 is used for etching InP, but carbon polymer films deposited on the surface during the etching process suppress the etching and degrade the surface quality. Thus, the polymer films must be ashed off in O2 plasma. The authors have introduced the cyclic injection of CH4/H2/Ar and O2 to ECR-RIBE and have demonstrated that it is very useful for the etching of InP. Concerning optimized etching conditions for achieving a high etching rate and smooth etched surface, it has been shown that the etching time and the ashing time should be the same in one cycle, and that the interval times should be as short as possible. Good vertical anisotropic characteristics have been achieved by cyclic etching using a three-layer resist with a Ti layer. From photoluminescence measurements, it has also been verified that this cyclic ECR-RIBE process did not cause any serious damage.