For VCSEL devices isolation
We have developed a process technology that enables high-speed vertical machining up to and including ø6 inch wafers. This shows an example of a GaAs mesa etching process with an etching rate of about 2 μm / min. A selectivity of about 18:1 to resist masks and 70:1 to SiN masks have been achieved. This process contributes to increased throughput in the fabrication of GaAs VCSEL devices.