Abstract In this paper, the Ar/N 2 gas flow rates and annealing ambient dependence on ferroelectric HfN (Fe-HfN) formed by electron cyclotron resonance (ECR)-plasma sputtering were investigated. The remanent polarization (2P r ) of 1.3 µC/cm 2 and 1.2 µC/cm 2 were obtained with Ar/N 2 gas flow rates of 8/6 and 8/8 sccm, respectively. Fatigue endurance up to 10 10 cycles was achieved with Ar/N 2 gas flow rates of 8/8 and 8/10 sccm. Annealing in He ambient increased 2P r from 1.2 µC/cm 2 to 3.0 µC/cm 2 compared with annealing in N 2 ambient. PtSi source/drain Schottky-barrier MFSFETs (SB-MFSFETs) were fabricated with Ar/N 2 gas flow rates of 8/8 sccm and annealing in He ambient. An I ON /I OFF ratio of 5.9 × 10 3 and a subthreshold swing (SS) of 186 mV/dec were obtained. The I D –V G characteristics shifted in the positive direction after applying −3.7 V/100 ns pulses 100 times, indicating ferroelectric polarization switching.