Area-Selective Atomic Layer Deposition of Crystalline BaTiO₃

Abstract

Patterned, crystalline BaTiO 3 (BTO) films were formed directly on STO(001) surfaces using atomic layer deposition and restricting Ba and Ti precursor adsorption to STO(001) by passivating regions of the substrate with a polystyrene blocking layer. Patterns were prepared by spin-coating polystyrene onto STO(001), UVcrosslinking the polystyrene, and rinsing away uncrosslinked polystyrene with toluene. Amorphous 9−12 nm thick BTO films were deposited at 225 °C on polystyrene-patterned STO(001) surfaces. These films were crystallized upon annealing at elevated temperatures. Atomic force microscopy, scanning electron microscopy, and time of flight secondary ion mass spectroscopy were used after growth of BTO and removal of polystyrene resist and reveal BTO features with dimensions similar to the shadow mask. Reflection high-energy electron diffraction and X-ray diffraction show that BTO epitaxially crystallizes to the substrate, forming BTO(001), after annealing under vacuum at ≥770 °C with an oxygen partial pressure of 1 × 10 −6 Torr.

Vacuum Ultraviolet-Enhanced Oxidation—A Route to the Atomic Layer Etching of Palladium Metal

“…The dose of formic acid results in a pressure rise of 0.46–0.50 Torr over the baseline Ar pressure. The manifold is described in detail elsewhere . One ALE cycle consists of one oxidation step and Ar purge, which is then followed by one dose of formic acid and Ar purge.…”

“…The manifold is described in detail elsewhere. 31 One ALE cycle consists of one oxidation step and Ar purge, which is then followed by one dose of formic acid and Ar purge. Shorthand is used as followed to denote ■ RESULTS AND DISCUSSION Initial Surfaces of 2 nm Pd and 20 nm Pd.…”

Density Functional Theory Study of Oxygen Adsorption on Polymer Surfaces for Atomic-Layer Etching: Implications for Semiconductor Device Fabrication

“…Organic masks are ubiquitous in semiconductor device manufacturing. Such organic films are used to pattern the underlying substrate, thus allowing subsequent selective etching or ALD of any other material of interest . A schematic view of both processes is shown in Figure .…”

“…More specifically and because of its importance in practical etching processes for semiconductor device fabrication, here we address this issue by testing the role of oxygen atoms as the primary plasma species using DFT simulations and investigating the oxidation mechanisms, ultimately leading to etching of the polymer surface. We used fully hydrogenated and partially dehydrogenated PS as organic surface models because of its extensive prior use in both plasma-etching experiment and MD simulation publications. ,, PS is also widely used as a passivating blocking layer in patterns for ALD of complex oxides such as BaTiO 3 . Although reactive plasmas contain many different species, such as energetic ions or excited atoms, in this work we focus only on atomic and molecular oxygen, given that a proper description of excited-state species would require the use of computationally more demanding first-principles methods beyond standard DFT.…”

Atomic Layer Nucleation Engineering: Inhibitor-Free Area-Selective Atomic Layer Deposition of Oxide and Nitride

“…Nowadays, most of the AS-ALD approaches are based on the selective functionalization of GA and NGA by inhibitors. Self-assembled monolayers and polymer-based materials were widely used for the formation of a layer of self-aligned inhibitors on the NGA to block the film growth. − However, the full coverage of inhibitors on NGA takes a long time and an additional step is required to remove inhibitors, which results in selectivity loss and a significant impact on the throughput and yield. The poor thermal stability of inhibitors also imposes process temperature limitation of ALD .…”