Atomic layer deposition of perovskite oxides and their epitaxial integration with Si, Ge, and other semiconductors

Abstract

Atomic layer deposition (ALD) is a proven technique for the conformal deposition of oxide thin films with nanoscale thickness control. Most successful industrial applications have been with binary oxides, such as Al2O3 and HfO2. However, there has been much effort to deposit ternary oxides, such as perovskites (ABO3), with desirable properties for advanced thin film applications. Distinct challenges are presented by the deposition of multi-component oxides using ALD. This review is intended to highlight the research of the many groups that have deposited perovskite oxides by ALD methods. Several commonalities between the studies are discussed. Special emphasis is put on precursor selection, deposition temperatures, and specific property performance (high-k, ferroelectric, ferromagnetic, etc.). Finally, the monolithic integration of perovskite oxides with semiconductors by ALD is reviewed. High-quality epitaxial growth of oxide thin films has traditionally been limited to physical vapor deposition techniques (e.g., molecular beam epitaxy). However, recent studies have demonstrated that epitaxial oxide thin films may be deposited on semiconductor substrates using ALD. This presents an exciting opportunity to integrate functional perovskite oxides for advanced semiconductor applications in a process that is economical and scalable.

Recent studies of oxide-semiconductor heterostructures using aberration-corrected scanning transmission electron microscopy

“…All of the oxide-semiconductor heterostructures described here have been grown using either molecularbeam epitaxy (MBE) or atomic-layer deposition (ALD), techniques that are described in detail elsewhere. 5,12 MBE is widely recognized as the ideal technique for growing epitaxial layers of well-controlled stoichiometry and excellent crystallinity. For the samples described here, the MBE growth has been carried out using a customized DCA-600 system with a base pressure of 3 Â 10 À10 Torr.…”

Separation of the Metallic and Dielectric Losses of Tunable Ferroelectric Capacitors Under Control Dc Voltage

“…It will be interesting to use the procedure for FE varactors with not commonly used metal/FE structures, but with actively developed nowadays semiconductor/FE structures [11].…”

Atomic layer deposition of perovskites—Part 1: Fundamentals of nucleation and growth

“…We have seen that the growth rate of ternary compounds is not a direct combination of the growth rate of binaries. In most cases, the growth rate is higher than anticipated, due to higher surface reactivity between precursor ligands and interfacial functional groups . To have an understanding of how the growth is affected by the different interfaces, we are focusing on the nucleation/wetting aspect, that is, how respective binaries grow on different substrates.…”

“…In most cases, the growth rate is higher than anticipated, due to higher surface reactivity between precursor ligands and interfacial functional groups. 20 To have an understanding of how the growth is affected by the different interfaces, we are focusing on the nucleation/wetting aspect, that is, how respective binaries grow on different substrates. This is especially important for ternaries; once a binary is deposited, it becomes the substrate for the other binary.…”