Charge trapping behavior in organic–inorganic alloy films grown by molecular layer deposition from trimethylaluminum, p-phenylenediamine and water

Abstract

Organic-inorganic hybrid or alloy films have great potential as a functional material because they have structural flexibility owing to the presence of an organic moiety. Here organic-inorganic hybrid films were grown by molecular layer deposition (MLD) by using trimethylaluminum and p-phenylenediamine. Although the hybrid films could be grown via the self-limiting growth mechanism of MLD, the hybrid films were severely air sensitive. The stability problem of the hybrid films could be solved by alloying the hybrid layer with Al 2 O 3 layers. The alloy films, which were grown by repeating supercycles with one subcycle for the hybrid layer and four subcycles for the Al 2 O 3 layers, showed excellent dielectric properties: a leakage current density of $2.3 Â 10 À8 A cm À2 at 1 MV cm À1 ; a dielectric breakdown field at $2.9 MV cm À1 ; and a dielectric constant of $6.2. Interestingly, charge trapping behavior was clearly observed in the alloy film. The charge trapping ability of the alloy film was verified with a charge trapping memory capacitor in which the alloy film was inserted as a charge trapping layer.

Reversible and Irreversible Reactions of Trimethylaluminum with Common Organic Functional Groups as a Model for Molecular Layer Deposition and Vapor Phase Infiltration

“…However, only one publication described the MLD process involving TMA and 4‐phenylenediamine, which works at 400 °C. The resulting film is unstable and decomposes upon contact with humidity . Furthermore, for ALD processes it is known that aluminum oxide is much easier to grow than aluminum nitride .…”

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

“…The obtained films were unstable: An increase of ca. 30% in film thickness was observed when the films were kept in ambient air for two weeks [ 34 ].…”

Organic–Inorganic Thin Films from TiCl4 and 4‐Aminophenol Precursors: A Model Case of ALD/MLD Hybrid‐Material Growth?

“…[2] Many of the applications of hybrid materials, both the current applications and the potential new ones, require the material to be in thin-film form. [5][6][7][8][9][10][11][12][13][14] Although the history of ALD goes back to the 1960s [15] and 1970s, [16] and even though MLD was introduced already in the 1990s, [17][18][19][20][21] the two techniques were only re- cently combined to synthesize organic-inorganic hybrids. [3,4] The sequential manner of deposition sition of (Ti-O-C 6 H 4 -N=) n thin films from precursors TiCl 4 and 4-aminophenol (AP) with the essentially ideal growth rate of 10-11 Å per ALD/MLD cycle.…”

“…Atomic layer deposition (ALD) is an advanced thin-film-deposition technique based on sequential surface-saturated deposition cycles, where each gaseous precursor pulse is separated by a purging pulse of inert gas. So far, hybrid thin films based on various metal alkoxides, [22][23][24][25][26][27][28][29][30][31][32] carboxylic acids, [33][34][35][36] and amines [33,[37][38][39] have been produced. We attribute the steady growth of the Ti-AP hybrid to the following facts: (1) the AP molecule is heterobifunctional and consists of a stiff aromatic backbone; moreover, (2) the -Cl ligands in TiCl 4 are small enough not to cause steric hindrance.…”