Fabrication of thin ferroelectric Hf0.5Zr0.5O2 films by millisecond flash lamp annealing

Abstract

We used millisecond flash lamp annealing (FLA) to form thin ferroelectric Hf0.5Zr0.5O2 (HZO) films with thicknesses of less than 10 nm and with remanent polarization up to 30 μC cm−2. A clear dependency of the polarization on the annealing temperature and time was observed, indicating that the precise management of the thermal budget is a key factor in forming ferroelectric HZO. We also show and compare the process windows within which ferroelectricity in 10 and 5 nm samples is obtained. The results show that a high thermal budget is necessary for thinner samples. We examined the endurance characteristics and a greater endurance compared to rapid thermal annealing treatment was observed with more than 1010 cycles without breakdown confirmed in 5 nm thick samples. The data indicates that there is the possibility of further thickness scaling whilst retaining highly durable characteristics for films annealed by FLA.