I have patterned long rectangular trenches with "vertical" sidewalls onto (311)B GaAs substrates. The trenches are aligned perpendicular to the major flat, and the wafers have a standard US orientation.

I'm having an issue definitively labelling / assigning the sidewall planes, and some higher-index planes I can see. Does anyone have, or know of, a good reference for labelling planes on patterened (311) (and other higher-index orientation) wafers?

p.s. I think the sidewalls are (0-11) planes, but can't say that for sure.