Oxford III-V
About
Process: This is a high-density plasma reactive ion etcher (RIE/ICP) optimized for III-V compound semiconductors, 2D materials, and other advanced semiconductors. It supports both room-temperature and cryogenic etching for smooth sidewalls, high selectivity, and low damage—critical for photonic, electronic, and quantum devices.
Hardware: Inductively Coupled Plasma (ICP) source with separate coil (up to 1500 W) and table RF bias (up to 1500 W). Cryogenic cooling capability (down to -120°C) for reduced sidewall roughness and improved profiles in III-V etching. Helium backside cooling for temperature uniformity. 4" wafer clamp standard; carrier wafers for smaller pieces. Optical endpoint detection (Horiba Jobin Yvon LEM G50) for precise process termination.
Gases:
- Ar (argon – physical sputtering/milling)
- O₂ (oxygen – ashing or oxidation enhancement)
- SF₆ (sulfur hexafluoride – fluorine-based etching)
- CH₄ (methane – for III-V etching with polymer control)
- H₂ (hydrogen – reduction or sidewall passivation)
- Cl₂ (chlorine – high-rate etching of III-Vs)
- BCl₃ (boron trichloride – chlorine-based etching with selectivity)
- SiCl₄ (silicon tetrachloride – for specific III-V or Si etching)
Etch Properties:
- Smooth, vertical sidewalls (especially at cryo temps)
- High selectivity to masks (e.g., SiO₂, metals, resists)
- Low damage to III-V surfaces (important for optoelectronics)
- Tunable profiles via temperature, gas ratios, and bias
- Wide temperature range (-120°C to 200°C) for process flexibility
Applications:
- Mesa etching for lasers, LEDs, and photodetectors (InP, GaAs, GaN)
- Waveguide and photonic crystal fabrication
- Nanowire and quantum dot definition
- Etching of 2D materials (MoS₂, WSe₂, graphene)
- ITO patterning for transparent electrodes
- High-selectivity etches in compound semiconductor devices
Usage: Load wafer (4" clamp or carrier), pump down, select/load recipe, set temperature (cryo or heated), power, gas flows, run process. Use endpoint detection for timed/auto-stop. Monitor profile and damage post-etch (e.g., SEM).
Detailed Specifications
- Model: Oxford PlasmaPro 100 Cobra III-V etcher
- Location: Etch bay 1
- Substrate size: 4" wafer clamp standard; smaller pieces on carrier wafers; 2", 3", 4", 6", 8" possible
- Table temperature: -120°C to 200°C (cryo cooling + helium backside cooling)
- Plasma power:
* ICP coil: up to 1500 W * Table RF bias: up to 1500 W
- Gases: Ar, O₂, SF₆, CH₄, H₂, Cl₂, BCl₃, SiCl₄
- Features: Cryogenic capability, optical endpoint detection (Horiba Jobin Yvon LEM G50), high selectivity/low damage for III-Vs and 2D materials
- Restrictions: No exposed metals (except Cr); no deep etching polymers (>1 µm)
- Other: Optimized for compound semiconductors, excellent sidewall smoothness at cryo temps
Documentation
- SOP – Standard Operating Procedure
- Quickstart Guide
- Training required – contact lab staff (Joey)
Recipes & Data
- Standard Recipes: Check internal process logs or lab spreadsheets for III-V etches (e.g., GaAs/InP mesas with Cl₂/BCl₃/Ar, GaN with Cl₂/Ar, cryo Si etch, 2D material patterning)
- Process Control: Measure etch depth/profile/smoothness via SEM or AFM. Check selectivity and surface damage (e.g., via PL or electrical tests). Perform test etches and particle scans.
- Notes: Use cryo mode for reduced roughness in III-V etching. Adjust CH₄/H₂ ratios for polymer control. Monitor mask erosion for selectivity.
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