ABSTRACT Achieving high‐throughput, low‐damage preparation of indium phosphide (InP) surfaces remains challenging because increasing the material removal rate (MRR) in chemical mechanical polishing (CMP) often compromises ultralow roughness and requires post‐CMP passivation, which can lead to secondary etching. In this work, an ammonium hexafluorophosphate (NH 4 PF 6 ) assisted CMP process is developed to incorporate directly into the polishing process via in situ fluoride passivation. Hexafluorophosphate (PF 6 − ) undergoes In 3 + ‐catalyzed hydrolysis, continuously producing fluoride‐rich intermediates that rapidly fluorinate InP, suppress oxide/defect formation, and concurrently generate an InF 3 ‐rich, mechanically compliant reaction layer that is readily stripped by SiO 2 abrasives; partial dissolution to soluble hexafluoroindate (InF 6 3 − ) further removes reaction products and sustains fast chemical–mechanical turnover. This approach achieves an MRR of 424 nm min −1 with a root‐mean‐square roughness (Sq) of 0.0862 nm. The fluoride‐passivated surfaces show improved optical quality, including longer time‐resolved photoluminescence (TRPL) lifetimes, higher photoluminescence quantum yields (PLQY), and more uniform emission, underscoring the promise of in situ fluoride passivation for scalable, device‐relevant InP surface preparation.
Fu et al. (Thu,) studied this question.