One-Step, High-Removal-Rate and Low-Damage Chemical Mechanical Polishing of InP Enabled by Hydrolysis Activated PF₆ ^-...

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 (NH₄PF₆) assisted CMP process is developed to incorporate directly into the polishing process via in situ fluoride passivation. Hexafluorophosphate (PF₆ ^-) undergoes In^{3 +}-catalyzed hydrolysis, continuously producing fluoride-rich intermediates that rapidly fluorinate InP, suppress oxide/defect formation, and concurrently generate an InF₃-rich, mechanically compliant reaction layer that is readily stripped by SiO₂ abrasives; partial dissolution to soluble hexafluoroindate ([InF₆]^{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.