ELECTRICAL EVALUATION OF SIDEWALL DAMAGE CAUSED BY CH4 H-2 REACTIVE ION ETCHING/

Electrical properties of p-n junction mesa diodes damaged at the sidew alls by reactive ion etching (RIE) with a mixture of methane (CH4) and hydrogen (H-2) were investigated. An InAlAs/InP/InAlAs double heteros tructure was used to suppress the n = 1 diffusion current and, consequ ently, to study the n congruent to 2 recombination current at the mesa -etched sidewall. The extent of damage layer at the sidewall was clari fied from the dependence of n congruent to 2 recombination current on the wet etching. Damaged-layer thickness of 60 to 90 nm was estimated from a comparison with the n congruent to 2 recombination current of w et-etched mesa diode.