Achieving enhanced electroless Ni-P plating on 6H-SiC substrate through optimization of plasma activation durations

Abstract

This study explores the impact of plasma activation on the surface properties of 6H-SiC substrates and the subsequent characteristics of electroless nickel‑phosphorus (NiP) plating. The research investigates how varying plasma activation durations influence surface roughness, chemical composition, and plating adhesion. Plasma activation significantly increased surface roughness from 592 nm to 772 nm and the oxidation layer thickness from 5.76 nm to 32.2 nm. These changes were accompanied by corresponding decreases in water and NiP solution contact angles, indicating enhanced surface wettability. The electroless NiP plating demonstrated a progressive increase in surface roughness, and the Ra roughness reached 1319 nm. X-ray diffraction (XRD) analysis revealed a reduction in the crystallinity of the NiP layer, alongside the emergence of new phases such as Ni₂P and Ni₈P₃, indicating alterations in the structural and chemical composition of the plating. The average thickness of the NiP plating decreased from 39.70 μm at 10 min of plasma activation to 36.12 μm at 30 min, suggesting a potential reduction in deposition efficiency with prolonged activation times. Additionally, the hardness of the NiP layer exhibited a decline from 525 HV to 502 HV, attributed to increased surface oxidation and defect formation. The adhesion quality of the plating also deteriorated with increased plasma activation time, as evidenced by significant peeling and cracking, as observed in the scratch test.