Atomic layer deposition of ruthenium at 100 °C using the RuO₄-precursor and H₂

Abstract

In this paper we report a low temperature (100 degrees C) ALD process for Ru using the RuO4-precursor (ToRuS (TM)) and H-2 as the reactant. The thermal decomposition behaviour of the precursor in the range of 50 degrees C-250 degrees C was investigated and it was found that thermal decomposition of RuO4 to RuO2 starts at a sample temperature of 125 degrees C. The RuO4/H-2 process (0.0045 mbar/4 mbar) was attempted at temperatures below this decomposition limit and it was found that ALD growth of pure Ru is possible in a narrow temperature window near 100 degrees C. The growth rate during steady state growth was found to be 0.1 nm per cycle. The Ru film nucleated easily on a wide range of substrates (H-terminated Si, TiN, Pt and Al2O3). Although the films are grown at a low temperature, they are considerably pure and are of good quality as evidenced by a resistivity of 18 mu Omega cm for an 18 nm film and a relative atomic concentration of impurities <5% as determined by XPS. It is hypothesized that the reaction of the RuO4 molecule with the Ru-surface leading to a monolayer of RuO2 is the mechanism that ensures a self-saturated behaviour of the first half reaction, which is a critical requirement to achieve a well-behaved ALD process

Mobile setup for synchrotron based in situ characterization during thermal and plasma-enhanced atomic layer deposition

“…These results are in line with our earlier findings based on in situ SE growth curves, and the easy nucleation on Si-H can be explained by the oxidizing nature of the RuO 4 molecule in combination with the oxidizable nature of the Si-H surface. 37 From Figure 5 plasma helps to initiate nucleation on SiO 2 . The growth curve for the plasma-based ALD process shows a ca.…”

Kinetics and Coverage Dependent Reaction Mechanisms of the Copper Atomic Layer Deposition from Copper Dimethylamino-2-propoxide and Diethylzinc

“…Although the ALD mechanisms of metal oxides are well understood, [27][28][29] very few theoretical [30][31][32] and in situ experimental 33,34 works have been dedicated to understand the reaction mechanisms of copper and related metals. Dey et al used a gas phase model to study the reactions of several common Cu precursors with Et 2 Zn.…”

Area-selective Ru ALD by amorphous carbon modification using H plasma: from atomistic modeling to full wafer process integration

“…4 There are different ways to achieve an inhibition of material growth on a dielectric surface. Typically, surface sensitive deposition techniques are used, such as ELD 8 and ALD 4,9,10 . In some of the cases, deposition technique possesses intrinsic selectivity to the material combination used in the stack.…”