Copper Oxide Films Grown by Atomic Layer Deposition from Bis(tri-n-butylphosphane)copper(I)acetylacetonate on Ta, TaN, Ru, and SiO[sub 2]

Abstract

The thermal atomic layer deposition (ALD) of copper oxide films from the nonfluorinated yet liquid precursor bis(tri- n -butylphosphane)copper(I)acetylacetonate, [(Bnu3normalP)C2normalu(acac)] , and wet O2 on Ta, TaN, Ru, and SinormalO2 substrates at temperatures of <160°C is reported. Typical temperature-independent growth was observed at least up to 125°C with a growth-per-cycle of ∼0.1Å for the metallic substrates and an ALD window extending down to 100°C for Ru. On SinormalO2 and TaN, the ALD window was observed between 110 and 125°C , with saturated growth shown on TaN still at 135°C . Precursor self-decomposition in a chemical vapor deposition mode led to bimodal growth on Ta, resulting in the parallel formation of continuous films and isolated clusters. This effect was not observed on TaN up to ∼130°C and neither on Ru or SinormalO2 for any processing temperature. The degree of nitridation of the tantalum nitride underlayers considerably influenced the film growth. With excellent adhesion of the ALD films on all substrates studied, the results are a promising basis for Cu seed layer ALD applicable to electrochemical Cu metallization in interconnects of ultralarge-scale integrated circuits.

Growth of ∼5 cm2V−1s−1 mobility, p-type Copper(I) oxide (Cu2O) films by fast atmospheric atomic layer deposition (AALD) at 225°C and below

“…Although much work has been devoted to the growth of metallic Cu interconnects by ALD, very little attention has been put on the growth and characterization of copper oxides. 23,24 In this work, we have used a novel spatial atmospheric atomic layer deposition system (AALD) to grow and characterize high quality Cu 2 O films at low temperatures (≤ 225 • C). Our AALD uses a shower-head type of approach whereby the precursors are simultaneously distributed over the sample to be coated while kept apart by a inert N 2 flow.…”

Surface chemistry of a Cu(I) beta-diketonate precursor and the atomic layer deposition of Cu2O on SiO2 studied by x-ray photoelectron spectroscopy

“…In addition, when the ALD Cu 2 O film on SiO 2 from the pure precursor 2 was compared with the mixture of the 2 and 7, no remarkable difference in the growth per cycle, film roughness, and morphology was observed. 8,28 Hence, in-situ surface investigations are carried out only with respect to precursor 2 in the current study, because it was seen before that the ALD growth of the Cu 2 O films was not affected by the addition of the catalytic amounts of precursor 7.…”

“…7 Recently, ultrathin films of Cu 2 O are applied as the material to obtain copper (Cu) seed layers for electrochemical deposition (ECD) of metallic Cu in the ultralarge scale integrated electronic devices. 8,9 The currently used physical vapor deposition processes for the deposition of the Cu seed layers, such as sputtering, are prone to nonconformal deposition within deep trenches. 10,11 This may cause failure of interconnections due to formation of voids after Cu ECD, making applications in future technology nodes questionable.…”

“…1) and wet O 2 as coreactant, was successfully carried out on different substrates such as SiO 2 , Ta, TaN, and Ru. 8,9,14 However, still many questions are unanswered regarding the underlying surface chemistry of this Cu precursor on many substrates, leading to different growth modes during ALD. 14 In previous studies related to the [15][16][17][18] In these chemical reactions, the volatile Cu(II) byproducts, copper(II) hexafluoroacetylacetonate or Cu(II) (2-methyl-3,5-hexandionate), and the dissociated ligands (L), vinyltrimethylsilane or 2-methyl-1-hexene-3-yne or trimethylphosphine or (bis(trimethylsilyl)acetylene), are quite stable below 250 C and leave the substrate without decomposition…”

“…The Vapbox mixes the Cu precursor with the Ar carrier gas and delivers the vapor into the ALD chamber through heated lines. Since the Cu precursor used for the experiments has a low vapor pressure (0.02 mbar at 98 C), 8 the Vapbox was heated to a temperature T vap of 115 C, in order to obtain sufficient vapor pressure and for preventing condensation inside the Vapbox. For the ALD process, water was evaporated in a Bronkhorst controlled evaporator and mixer liquid delivery system heated at 80 C. During the precursor dosing steps and the purging steps of the ALD cycle, the water vapor was introduced into the bypass line.…”