By electrical characterization of thin films deposited by atomic layer deposition, HfxZr1−xO2 (HZO) is shown to be ferroelectric as-deposited, i.e., without any annealing step, using a thermal budget of 300 °C. By fabricating laminated HZO films rather than the traditional solid-solution HZO, a remanent polarization of Pr = 11 μC/cm2 and endurance exceeding 106 are obtained. Films grown on thermally reactive InAs semiconductor substrates showed capacitance–voltage modulation and hysteresis, which varied depending on interfacial oxide construction. Additionally, a trade-off between higher polarization and lower gate leakage was found when comparing different laminate structures and deposition temperatures. Scaling the thickness of the laminated oxides revealed that films remain ferroelectric at 6.5 nm with an increased breakdown field for thinner devices.
- Annan elektroteknik och elektronik