Thermal Atomic Layer Deposition of Continuous and Highly Conducting Gold Thin Films

Abstract

Five Au(III) compounds were synthesized and evaluated for atomic layer deposition of Au thin films. One of the compounds, Me 2 Au(S 2 CNEt 2 ), showed optimal thermal characteristics while being volatile and thermally stable. In the growth experiments, this compound was applied with O 3 at temperatures of 120−250 °C. Self-limiting growth was confirmed at 180 °C with a rate of 0.9 Å/cycle. The deposited Au thin films were uniform, polycrystalline, continuous, and conductive. Typical resistivity values of 40 nm thick films were 4−16 μΩ cm, which are low for chemically deposited thin films. The chemical composition of a Au thin film deposited at 180 °C was analyzed by time-of-flight elastic recoil detection analysis, proving the film was pure with small amounts of impurities. The detected impurities were O (2.9 atom %), H (0.9 atom %), C (0.2 atom %), and N (0.2 atom %).

Controlling the Thermal Stability and Volatility of Organogold(I) Compounds for Vapor Deposition with Complementary Ligand Design

“…Films deposited by ALD are highly conformal to substrate geometry, and sub‐nanometer thickness control can be easily achieved by changing the number of sequential reactant exposures (i.e., cycles). Recently, two different ALD processes to deposit gold metal were reported using organogold(III) precursors: one by our group using oxygen‐plasma and water as co‐reagents, and the other by Mäkelä and co‐workers using ozone , . While both processes were effective at depositing gold metal with high growth rates at low temperatures, they inherently suffer similar limitations in their scope.…”

Thermal Ranges and Figures of Merit for Gold-Containing Precursors For ALD

“…for ALD of highly conductive gold metal films using O3 as a co-reagent and was the second reported process for gold ALD. 18 Compounds 16-18 do not perform well: the phenyl and quinoline backbones make these compounds quite non-volatile, especially in the case of 17 and 18. While TG data is reported for these two compounds, the residual mass is substantially higher than the % mass of Au in the original compound.…”

Thermal atomic layer deposition of gold nanoparticles: controlled growth and size selection for photocatalysis

“…10 Two successful studies on ALD of Au include a plasma process at 120°C using (trimethylphosphino)trimethylgold(III) as metal precursor; and a thermal process at 180°C, with dimethylgold(III)(diethylthiocarbamato) as metal precursor. 30,31 In both studies, the deposition was carried out on flat substrates under vacuum conditions. While such processes are certainly promising for a number of applications, plasma and vacuum processes are not readily scalable to large quantities of high-surface-area supports, which are relevant for catalytic applications.…”