On the development of an electrolyte for ECV profiling of AlInAs

AlInAs layers latticed matched to InP are important for the fabrication of high speed electronic and opto electronic devices. In this work, we present the realisation of three different electrolytes for ECV measurements of AlInAs. A comparison with the behaviours of the different electrolytic solutions has been discussed. Among the new electrolytic solutions, 1HNO₃:20H₂O::1HF:25H₂ O and NH₄F (0.75M) solutions were suitable for ECV profiling of AlInAs. They have low electrolytic resistance and free chemical etch rate values with good Schottky barrier characteristics. They are able to distinguish between n-type and p-type carriers and the variation in their concentration levels in addition to compatibility with the InP substrate material. But during profiling, formation of flakes has been noticed as the junction was approached. ECV estimated carrier concentration values and expected values agree, but the ECV measured thickness values do not agree well with the stylus profiler measured thickness values. Although these electrolytic solutions may be useful in principle for profiling of AlInAs/InP structures, further experiments are required to understand the mechanism of the dissolution of AlInAs thereby completely realising an electrolyte for a successful ECV profiling of AlInAs