Aluminum Nitride Nanofilms by Atomic Layer Deposition Using Alternative Precursors Hydrazinium Chloride and Triisobutylaluminum

Abstract

The aim of this study is motivated by the pursuit to investigate the performance of new and as yet untested precursors such as hydrazinium chloride (N2H5Cl) and triisobutylaluminum Al(C4H9)3 in the AlN atomic layer deposition (ALD) process as well as to study effects of successive annealing on the quality of the resulting layer. Both precursors are significantly cheaper than their conventional counterparts while also being widely available and can boast easy handling. Furthermore, Al(C4H9)3 being a rather large molecule might promote steric hindrance and prevent formation of undesired hydrogen bonds. Chemical analysis is provided by X-ray photoelectron spectroscopy (XPS) and secondary-ion mass spectrometry (SIMS) techniques; surface morphology was studied using atomic force microscopy (AFM). Chlorine containing precursors such as AlCl3 are usually avoided in ALD process due to the risk of chamber contamination. However, experimental data of this study demonstrated that the use of N2H5Cl does not result in chlorine contamination due to the fact that temperature needed for HCl molecules to become reactive cannot be reached within the AlN ALD window (200–350 °C). No amount of chlorine was detected even by the most sensitive techniques such as SIMS, meaning it is fully removed out of the chamber during purge stages. A part of the obtained samples was subjected to annealing (1350 °C) to study effects of high-temperature processing in nitrogen atmosphere, the comparisons with unprocessed samples are provided.

Amorphous AlN films grown by ALD from trimethylaluminum and monomethylhydrazine

“…Crystallinity generally increases with the deposition temperature, however according to the literature most of the AlN films grown both at relatively low and high temperatures are crystalline. [18][19][20][21][22][23][24][25] This fact indicates that the major contributing factor leading to a decrease in the crystallinity is apparently not the deposition temperature but the chemical structure of MMH. Namely, the suppression in crystallinity is likely resulting from the presence of methyl groups in the MMH molecules, which upon reaction at the surface occupy more space than NH 3 or N 2 H 4 , thereby disturbing the order and suppressing the crystallite growth.…”

“…Amorphous AlN films are of particular interest due to their improved mechanical, electrical and optical properties compared to those of the crystalline phase of AlN. [14][15][16][17] However, most AlN films grown by ALD are of crystalline nature [18][19][20][21][22][23][24][25] hence obtaining amorphous AlN films by ALD is an actual problem. AlCl 3 with NH 3 is a common precursor combination that has often been used for depositing AlN.…”

Area-Selective Low-Pressure Thermal Atomic Layer Deposition of Aluminum Nitride

“…Besides this classic set of precursors, other precursors and combinations have been introduced. Alternative nitrogen precursors are forming gas (N 2 + H 2 ), ,− hydrazine (N 2 H 4 ), − hydrazinium chloride (N 2 H 5 Cl), and monomethyl hydrazine (N 2 CH 6 ) . Alternative metal precursors are AlCl 3 , ,− TEA, , TMAA, , TDMAA, ,− DMEAA, − TDEAA, TiBA, and DMAA .…”

Multiferroic behavior of the functionalized surface of a flexible substrate by deposition of Bi2O3 and Fe2O3

“…There are several working deposition methods, all with their own capabilities and limitations, like molecular beam epitaxy (MBE) (Ueno, Okaura, Funakubo, & Saito, 2005), metal–organic vapor deposition (MOCVD) (Kabelac, Ghosh, Dobal, & Katiyar, 2007; Ueno et al, 2005) and pulsed layer deposition (PLD) (Yang et al, 2005), but these all struggle when trying to deposit a uniform and precisely detailed thin layer of BFO at low temperatures. The only method that is able to clear all these requirements is atomic layer deposition (ALD) (Abdulagatov et al, 2018; Dallaev, Sobola, Tofel, Škvarenina, & Sedlák, 2020; George, 2010; Puurunen, 2005), which is the reason why it is used to prepare BFO layers in this paper.…”