Atomic Layer Deposition of Copper Oxide using Copper(II) Acetylacetonate and Ozone

Abstract

We report on the deposition of copper oxide by atomic layer deposition (ALD) using copper acetylacetonate (Cu(acac) 2 ) and ozone (O 3 ) as precursors. The aim is to deposit oxides of copper as possible candidates for materials in all-oxide photovoltaics. The present study results in ALD-type deposition of the tenorite phase of copper(II) oxide in a temperature window of 150 8C to ca. 230 8C, with a growth rate of $0.038 nm per cycle. The resulting ALD characteristics, with a relatively large ALD window in deposition temperature, should be well suited for combination with additional deposition processes for the formation of complex compounds. The film thickness is studied using X-ray reflectivity (XRR), and phase is determined by X-ray diffraction (XRD). Surface roughness is studied using atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) is used to investigate the chemical state of the deposited films.

Surface chemistry of copper metal and copper oxide atomic layer deposition from copper(ii) acetylacetonate: a combined first-principles and reactive molecular dynamics study

“…As reported in the literature, when the H plasma is used for Cu(acac) 2 , the ALD window is as low as 85-135 1C. 21 However, much higher temperatures are required when ozone (150-230 1C) 11 or water (210-300 1C) 76 is used as the co-reactant. These results may suggest that the plasma H is more reactive towards Cu(acac) 2 as compared to ozone and water, which is consistent with our conclusion.…”

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.…”

“…38,[40][41][42][43] Figure 2(a) shows SEM images of films deposited at temperatures ranging from 125 to 225 • C. The films are fine grained and show an expected increase in grain size with temperature, from <50 nm at 125 • C to ∼ 150 nm at 225 • C. The granular structure of the films is as expected for the high growth rates and relatively large thicknesses of the films which forms by 3 dimensional nucleation and growth consistent with CuO films grown under similarly high rates by conventional ALD. 24 Figure 2(b) shows low resolution TEM images of a film deposited at 150 • C. The film is uniform and dense, as determined from scans across many different regions of the sample, with no visible cracks or porosity. High resolution TEM images taken from the edges of the film which are sufficiently thin for this purpose (a representative region is shown in Figure 2(c)) shows the sample to be crystalline with a lattice spacing matching that of Cu 2 O".…”

Deposition of copper from Cu(i) and Cu(ii) precursors onto HOPG surface: Role of surface defects and choice of a precursor

“…For example, Cu(hfac)VTMS (copper(i) hexafluoroacetylacetonate vinyl trimethylsilane) and Cu(hfac) 2 (copper(ii) hexafluoroacetylacetonate) are common precursors for ALD or CVD methods and are used to produce either coppercontaining nanoparticles or continuous thin films. [18][19][20][21][22] Due to the structural differences of the two precursors, different reactivities and therefore surface morphologies of the structures produced are expected, as has been observed on surfaces such as ZnO, 22 silica, and silicon. 18,20,21 In addition, since the VTMS moiety from Cu(hfac)VTMS is expected to desorb from the substrate immediately upon adsorption, as was observed on several substrates even at room temperature, [20][21][22][23][24][25][26][27] Cu(hfac) is actually expected to be the reactive adsorbate (Figure 1(a)) that will interact with the surface for deposition based on this precursor.…”