Emerging ferroelectric thin films: Applications and processing

Ferroelectrics possess a variety of interactions between electrical, mechanical, and thermal properties, enabling numerous functionalities. Integration of these functionalities into semiconductor integrated circuit platforms is of extreme interest. Ultra-thin ferroelectric films with uniform, conformal, and controllable thickness are promising for advancement in technology of future ferroelectric-based devices. Most well-known ferroelectric materials come from the metal oxide-based perovskite class, which causes severe issues for integration. The discovery of ferroelectricity in hafnium oxide-based materials brought a renewed interest into this field over the last decade. The tunable dielectric, ferroelectric, and piezoelectric properties of barium strontium titanate (BST) make it a promising candidate for the development of next-generation devices. Strong ferroelectricity is observed in wurtzite-type ferroelectrics like aluminum scandium nitride (AlScN), extending the potential of seeing a wealth of ferroelectric functions in integrated electronics in the future. This chapter presents three promising ferroelectric materials—HfO2-based, BST, and AlScN deposited using different deposition techniques: atomic layer deposition (ALD), pulsed laser deposition (PLD), and molecular beam epitaxy (MBE). A brief review is provided on the emerging applications and reliability issues are presented.