Hello,

  I would like some advice on plasma ashing on AlGaAs/ GaAs.

  A Ti/Au metal lift off seems to have left some aggressive photoresist
  (AZ 4214)  residue (at least that's what I think the black stuff is) on the
AlGaAs
  surface, which won't get removed with Acetone/IPA.

  I am considering an oxygen plasma clean up, but unsure if that would change
the
  surface chemistry in anyway. What should be the ashing conditions, and do I
need
  additional cleaning steps before proceeding with citric/peroxide selective
etching?


  Thank you,

  Sabarni Palit
  Duke University, Durham NC