Effects of Post-Deposition Annealing on the Electrical Properties of HfSiO Films Grown by Atomic Layer Deposition

Post-deposition annealing was investigated for hafnium silicate films deposited on Si substrates by atomic layer deposition. Annealing in NH 3 at 750°C incorporated 13 At.% nitrogen in hafnium silicate, and hysteresis significantly depended on film thickness. In contrast, annealing in N 2 at 950°C suppressed hysteresis and its dependence on the film thickness. In addition, effective mobility and positive bias temperature instability were improved by N 2 annealing of as-deposited hafnium silicate films. Finally, additional N 2 annealing following NH 3 annealing was effective to obtain highly dense hafnium silicate films with good mobility and optimized nitrogen incorporation.