Two component etchant for sawn semiconductor slices - esp. for removing damaged zones on gallium phosphide LEDs

摘要

Etching of sawn semiconductor slices esp. for LED's to remove light-absorbing surface damage caused by the sawing operation is effecting using an etchant which consists of two media neither of which attacks the slice unless it is mixed with the other medium; and mixing only occurs on those zones where etching is required. The etchant may be a mixt. of (a) H2SO4 and (b) H2O2; but (a) KOH soln. and (b) K3(Fe(CN)6) soln. (PFIC) are pref. for etching GaP slices. The pref. method is to saw a GaP slice, then pour KOH soln. over it and allow the excess to drain. The slice is then immersed in PFIC soln. so the latter mixes with the KOH in the saw grooves; and this method may be repeated.