AbstractThe use of dry hydrogen plasma etching is evaluated for determination of GaN polarity and critically compared to wet etching in NaOH. It is shown that hydrogen plasma etching is effective in revealing inversion domains (IDs) and some types of dislocations. This is because the surface morphology is unchanged by the hydrogen treatment, and, hence, the surface reactivity is not masked.
ABSTRACTWe have used in situ Auger spectroscopic analysis to investigate the composition of InP surfaces cleaned in rf H2 plasmas and etched in rf H2/CH4/Ar plasmas. In general agreement with previous results, hydrogen plasma treatment is found to remove surface carbon and oxygen impurities but also leads to substantial surface phosphorus depletion if not carefully controlled. Low plasma exposure times and rf power settings minimize both phosphorus depletion and surface roughening. Surfaces etched in H2/CH4/Ar plasmas can show severe phosphorus depletion in high density plasmas leading to etch rates of ∼ 700 Å/min, but this effect is greatly reduced in lower density plasmas that produce etch rates of 30–400 Å/min.