Review—Atomic Layer Deposition of Silicon Dioxide Thin Films

Abstract

This article provides a critical review of published experimental data for silicon dioxide thin films deposited using cyclic technologies, including thermally-activated (TA) and plasma-enhanced (PE) Atomic Layer Deposition (ALD). The studied precursors (cyanates, silicon chlorides, oxygen-containing reactants, amino silanes and heterocyclic compounds) have been analyzed historically with a search depth of about 25 years. The focus is on the aspects of film growth. The aminosilane precursor group has been comprehensively analyzed for the TA-ALD and PE-ALD processes using ozone and oxygen as oxidants, respectively. The deposition rates are on the level of 0.05–0.15 nm per process cycle on average. The deposition rate of PE-ALD shows gradual decrease with temperature for all investigated precursors. For TA-ALD processes, the deposition temperature decreases and the deposition rates increase with a decrease in the number of amino groups in the silane molecule, and with an increase in the ozone dose. Problems and solutions to the problem of thin film conformality in ALD processes are analyzed. Assumptions are made about the possible prospects for investigating TA-ALD processes using monosilane, oxygen and nitrous oxide at low deposition temperatures.

Atomic layer deposition of silicon oxide films using bis(dimethylaminomethylsilyl)trimethylsilylamine and ozone: first-principles and experimental study

“…The Dmol 3 package in Material Studio 7.0 (BIOVIA, USA) 22,23 was used for the DFT calculation. The double numerical polarization (DNP) 4.4 was used as the basis set, 22 and the generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) 24 was used as the exchange–correlation functional.…”

“…This is different from the case of aminosilane precursors, where the growth rate decreased with increasing process temperature. 3 The pathway to P b would dominate at low temperatures due to the lowest activation energy of 0.48 eV, as shown in Fig. 4.…”

“…The atomic layer deposition (ALD) of silicon oxide (SiO 2 ) film has been studied for dielectric materials in nano-scaled semiconductor devices. 1–3 The ALD technology ensures excellent step coverage, accurate thickness control, and excellent film quality at lower temperatures compared with the traditional chemical vapor deposition (CVD) technique. 4,5 The ALD silicon oxide films were applied in three-dimensional vertical NAND flash memories as the blocking oxide and tunneling oxide, 6,7 dynamic random access memory (DRAM) devices as gate spacers, 8 and self-aligned multiple patterning technologies as spacers.…”

“…Recently, Vasilyev reviewed the reports on the ALD of silicon oxide. 3 The silicon precursors used in the semiconductor industry can be categorized into silicon chlorides and aminosilanes. The ALD films prepared using silicon chloride precursors, such as SiH 2 Cl 2 10 and Si 2 Cl 6 , 11 and O 3 at 350–450 °C showed insulating properties comparable to those of CVD films deposited at higher temperatures.…”

Growth characteristics and properties of Ga2O3 films fabricated by atomic layer deposition technique

“…The sequential and self-saturating reactions ensure excellent conformality on high-aspect ratio structures, precise thickness control at the atomic scale, and high uniformity in both thickness and composition at a low substrate temperature. [52][53][54][55] ALD processes use either molecular species or reactive species in the plasma state as oxidizing or reducing reactant. The former process is termed thermal ALD since thermal energy is the only available energy source for reactions, while the latter is termed plasma-enhanced ALD (PEALD) since highly reactive radicals contribute to chemical reactions using a radio frequency power generator.…”