Hi Mikas,

It was 13 years ago, so whether the recipe for 1165 has changed I don't
know.

Doing lift-off, exposures of maybe half an hour up to several hours.
Room temperature.  My HEMTs had very poor properties and sometimes were
completely open-circuit.  The rate was slow, but I can't give you a
precise rate because I didn't calibrate it and it was a long time ago.
Order of a nanometre or two per hour is about right.  If you were simply
stripping resist and rinsing in water you'd be hard-pressed to tell
whether it was just the action of the water on the surface oxides, but a
long soak (e.g. a tricky lift-off) could certainly kill a HEMT.  Six
months of very long hours before I found that out.

Andy

mikas remeika wrote:
> In a recent post it was mentioned the Microposit 1165 attacks GaAs at
> some slow rate. Could anyone share their specific experiences
> regarding this? I.e. under what conditions the etch might occur and
> approximately what etch rate is expected? This is very worrying to me
> since the spec sheet seems to imply that 1165 is GaAs compatible.
>
> Also, what about Remover PG ? Are there any known semiconductors that
> it attacks?
>
> thank you,
> -mikas