Electrical Properties of Hafnium Dioxide

Since the discovery of graphene in 2004, there has been a renewed interest in 2D materials -which have the potential to increase efficiency and speed, and decrease cost, size, and power consumption within electronic devices. Current insulating material, such as silicon dioxide, limits our ability to comply with Moore’s Law -which predicts that the number of transistors within an integrated circuit doubles about every 2 years. To scale devices even further, hafnium dioxide (hafnia) has shown to be a suitable replacement in the gate oxide insulating layer in complementary metal oxide semiconductor devices due to its comprehensive performance. Atomic Layer Deposition of hafnia was grown and annealed at various temperatures between 1-2 hours and its electrical characteristics were examined. Results show that with an annealing temperature of 700C for 1 hour, the crystallinity of the bulk material improved significantly compared to lower temperatures regardless of the annealing time. Results also show that the capacitance remains nearly constant with increasing voltage frequency. Also, the dielectric loss remains the lowest in the same sample. However, the decrease in impedance shows no significant improvement among other samples annealed at different temperatures.