[labnetwork] Etching GaP with PhotoResist as a etch stop

[Hollingshead, David]

Hi Sa'ad,

We regularly use SPR220 or S1813 as masks for III-V etches in BCl3-based ICP etches. I wouldn't characterize them as an "etch stop" as they do etch to some degree. The selectivity is generally fairly good with III-V compounds however.

In our PlasmaTherm 770 ICP tool we typically see resist etch rates of ~30nm/min in a BCl3/Ar plasma. Depending on the III-V material we are etching this leads to a selectivity of at least 2.5:1, but often much better. The actual etch rates you see will vary depending on your equipment and etch conditions of course. Selectivity will likely be even better with low or no Ar flow if your devices can be etched in pure BCl3.

-Dave

Dave Hollingshead
Senior Research Associate - Nanotech West Lab
The Ohio State University
Suite 100, 1381 Kinnear Road, Columbus, OH 43212
614.292.1355 Office
hollingshead.19 at osu.edu<mailto:hollingshead.19 at osu.edu> osu.edu<http://osu.edu/>



From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of Sa'ad H
Sent: Monday, April 6, 2020 13:59
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Etching GaP with PhotoResist as a etch stop

I'm currently working on a process to etch GaP in BCl3. I know Zep works as an etch stop for BCl3, but I want to move away from Zep so I can use optical litho instead of ebeam. Does anyone know if standard photoresists (s1805) or SPR-220 (these are just examples) would work as etch stops?

Alternately, are there any hard masks or oxides that anyone could suggest?
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