Trimethylaluminum Research Articles

Al2O3 atomic layer deposition on a porous matrix of carbon fibers (FiberForm) for oxidation resistance

Atomic layer deposition (ALD) was used to coat a porous matrix of carbon fibers known as FiberForm with Al2O3 to improve oxidation resistance. Static trimethylaluminum (TMA) and H2O exposures for Al2O3 ALD were used to obtain the uniform coating of this high porosity material. The carbon surfaces were initially functionalized for Al2O3 ALD by exposure to sequential exposures of nitrogen dioxide and TMA. A gravimetric model was developed to predict the mass gain per cycle under conditions when the ALD reactions reached saturation during each reactant exposure. The uniformity of the Al2O3 ALD coating on FiberForm was confirmed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) analysis. The SEM, EDS, and gravimetric models were all consistent with a uniform Al2O3 ALD coating on the porous carbon fiber network when the ALD reactions reached saturation on the entire surface area. In contrast, the profile of the Al2O3 ALD coating on the FiberForm was also characterized using undersaturation conditions when the ALD reactions did not reach saturation throughout the FiberForm sample. Based on comparisons with results from models for ALD in porous substrates, these Al2O3 coverage profiles were consistent with diffusion-limited Al2O3 ALD. Oxidation of the FiberForm and the Al2O3 ALD-coated FiberForm was also investigated by thermogravimetric analysis (TGA). TGA revealed that a 50 nm thick Al2O3 coating deposited using 400 Al2O3 ALD cycles enhanced the oxidation resistance. The Al2O3 ALD coating increased the oxidation onset temperature by ∼200 °C from 500 to 700 °C. The oxidation of the FiberForm removed carbon and left the Al2O3 ALD coating behind as a white “skeleton” that preserved the shape of the original FiberForm sample. The Al2O3 ALD coating also decreased the oxidation rate of the FiberForm by ∼30%. The oxidation rate of the Al2O3 ALD-coated FiberForm samples was constant and independent of the thickness of the Al2O3 ALD coating. This behavior suggested that the oxidation is dependent on the competing O2 diffusion into the FiberForm and CO2 diffusion out of the FiberForm.

Modeling the impact of incomplete conformality during atomic layer processing

Atomic layer processing (ALP) is a modern fabrication technique for the deposition or etching of materials, which provides precise control of film thickness, composition, and conformality on a nanometer scale. This makes it crucial for the fabrication of high aspect ratio (HAR) structures, such as 3D NAND memory stacks, as its self-limiting nature provides enhanced conformality compared to traditional processes. However, as the number of NAND stacks grows and the aspect ratio continues to increase, deviations from full conformality can often occur due to precursor desorption from the surface. In this regard, a model for surface coverage during ALD in the presence of desorption, leading to incomplete conformality, has been developed and implemented in process simulation frameworks. This work is an extension of our previous research which concentrated on developing an accurate modeling approach for ALD in HAR structures (L.Aguinsky et al., Solid State Electron. 201, 2023). The model combines existing Knudsen diffusion and Langmuir kinetics methods and includes the Bosanquet formula for gas-phase diffusivity and reaction reversibility. It has been incorporated into academic and commercial level-set-based topography simulators. The parameters for the model have been calibrated using published results for the ALD of Al2O3 from trimethylaluminum (TMA) and H2O in HAR geometries. The temperature dependence of the H2O step is likewise analyzed, revealing an activation energy of 0.178eV, which is consistent with recent experiments. In the TMA step, the Bosanquet formula leads to improved accuracy, and the same parameter set is able to reproduce multiple experiments, demonstrating that the model parameters accurately capture reactor conditions. Finally, the developed model is combined with atomic layer etching (ALE) to simulate the controlled, conformal deposition of HfO2 inside HAR 3D NAND structures.

Engineering organic solvent reverse osmosis in hybrid AlOxHy / polymer of intrinsic microporosity 1 (PIM-1) membranes using vapor phase infiltration

A solvent-free post-treatment process known as vapor phase infiltration (VPI) is used to engineer the organic solvent reverse osmosis (OSRO) performance of polymer of intrinsic microporosity 1 (PIM-1) membranes via infiltration of trimethylaluminum (TMA) metal-organic vapor. The infiltration of inorganic aluminum constituents hybridizes the pure polymer PIM-1 into an organic-inorganic material (AlOxHy/PIM-1) with enhanced chemical stability. A homogenous distribution of inorganic loading in PIM-1 is achieved due to the reaction-limited infiltration mechanism, and the OSRO performance is enhanced as a result. OSRO separations of ethanol/isooctane mixtures using these membranes are shown to be capable of breaking the azeotropic composition with a separation factor for ethanol over isooctane greater than 5 and an ethanol permeance of 0.1 Lm–2h–1bar–1. Thus, these organic-inorganic hybrid membranes created via VPI show promise as an alternative method for separating azeotropic liquid mixtures.

Alumina layers deposited by atomic layer deposition with different precursors: Surface photovoltage measurements

The electrical and passivation properties of alumina layers deposited by the atomic layer deposition (ALD) technique with trimethylaluminium (TMA) and two different oxidants (ozone and water) and their mixture under different deposition conditions were investigated by using surface photovoltage. In all alumina layers negatively charged defects were observed after the ALD deposition. The density of interface states (Dit) and the density of negative charge (CFix) in as-deposited alumina layers prepared with water was found to be lower in comparison to wafers prepared with O3 or with a mixture of H2O and O3. The minority carrier diffusion length was also larger in wafers prepared with H2O and TMA. By comparing the deposition conditions of different alumina layers we concluded that interstitial oxygen could be responsible for the appearance of the negatively charged defects. After the broadband illumination we also observed a significant increase of CFix in all alumina layers independent of the precursors used for the deposition and only small changes of Dit were detected. O-related defects could also lead to such changes of CFix after the illumination.

1H‐Perfluorohexane—An efficient modifier for ethylene tri‐/tetramerization

Silicon‐bridged/N, P (PNSiP) ligand/Cr (III) catalyst system based on different fluorinated hydrocarbons as modifiers have been explored for ethylene selective tri‐/tetramerization. Modifiers like 1H‐Perfluorohexane (1H‐PFH), Hexafluorobenzene (HFB), and Perfluorobiphenyl (PFB) have been proven to show a significant influence on ethylene oligomerization toward 1‐hexene and 1‐octene of the catalytic system. Among them, 1H‐PFH showed the most significant promotion effect in improving activity from 0.95 × 106 g·(mol Cr·h)−1 to as much as 5.66 × 106 g·(mol Cr·h)−1 at high temperature 90°C. Through the analysis of nuclear magnetic resonance (NMR) spectroscopy and ultraviolet visible diffuse reflectance spectroscopy (UV–vis DRS) results, we concluded that 1H‐PFH can react with an amount of trimethylaluminum (TMA) contained in the cocatalyst modified methylaluminoxane (MMAO) and the solubility of Cr (III) in solvent can be increased after adding 1H‐PFH. Furthermore, the possible reaction routes of 1H‐PFH with TMA and MMAO were proposed.

Surface reaction during thermal atomic layer etching of aluminum oxide films using fluorine radicals and trimethylaluminum

We investigated the surface reaction of the thermal atomic layer etching (ALE) of Al2O3 film using fluorine (F) radicals and trimethylaluminum (TMA). As a strong fluorination source to replace HF, we used NF3 remote plasma to generate F radicals without spontaneous or anisotropic etching by ion bombardment. The mass was increased by F radicals and decreased by TMA. X-ray photoelectron spectroscopy (XPS) analysis showed that AlF3 and AlOxFy were formed by F radicals, and all AlF3 and a significant portion of AlOxFy were removed by TMA. At 250 °C, the etch per cycle (EPC) was fully saturated at 1.58 Å/cycle for the NF3 remote plasma of 4 s and the TMA pulse time of 3 s. Based on the saturation behavior, isotropic etching was demonstrated for the Al2O3 film prepared on a trench pattern. The EPC increased progressively with temperature from 0.1 Å/cycle at 198 °C to 4.2 Å/cycle at 320 °C. Since the thickness of the fluorinated layer did not increase significantly with increasing temperature, the removal step determined the EPC.

Area-Selective Deposition by Cyclic Adsorption and Removal of 1-Nitropropane.

The ever-greater complexity of modern electronic devices requires a larger chemical toolbox to support their fabrication. Here, we explore the use of 1-nitropropane as a small molecule inhibitor (SMI) for selective atomic layer deposition (ALD) on a combination of SiO2, Cu, CuOx, and Ru substrates. Results using water contact angle goniometry, Auger electron spectroscopy, and infrared spectroscopy show that 1-nitropropane selectively chemisorbs to form a high-quality inhibition layer on Cu and CuOx at an optimized temperature of 100 °C, but not on SiO2 and Ru. When tested against Al2O3 ALD, however, a single pulse of 1-nitropropane is insufficient to block deposition on the Cu surface. Thus, a new multistep process is developed for low-temperature Al2O3 ALD that cycles through exposures of 1-nitropropane, an aluminum metalorganic precursor, and coreactants H2O and O3, allowing the SMI to be sequentially reapplied and etched. Four different Al ALD precursors were investigated: trimethylaluminum (TMA), triethylaluminum (TEA), tris(dimethylamido)aluminum (TDMAA), and dimethylaluminum isopropoxide (DMAI). The resulting area-selective ALD process enables up to 50 cycles of Al2O3 ALD on Ru but not Cu, with 98.7% selectivity using TEA, and up to 70 cycles at 97.4% selectivity using DMAI. This work introduces a new class of SMI for selective ALD at lower temperatures, which could expand selective growth schemes to biological or organic substrates where temperature instability may be a concern.

An H2 O-Initiated Crosslinking Strategy for Ultrafine-Nanoclusters-Reinforced High-Toughness Polymer-In-Plasticizer Solid Electrolyte.

Incorporating plasticizers is an effective way to facilitate conduction of ions in solid polymer electrolytes (SPEs). However, this conductivity enhancement often comes at the cost of reduced mechanical properties, which can make the electrolyte membrane more difficult to process and increase safety hazards. Here, a novel crosslinking strategy, wherein metal-alkoxy-terminated polymers can be crosslinked by precisely controlling the content of H2 O as an initiator, is proposed. As a proof-of-concept, trimethylaluminum (TMA)-functionalized poly(ethylene oxide) (PEO) is used to demonstrate that ultrafine Al-O nanoclusters can serve as nodes to crosslink PEO chains with a wide range of molecular weights from 10000 to 8000000gmol-1 . The crosslinked polymer network can incorporate a high concentration of plasticizers, with a total weight percentage over 75%, while still maintaining excellent stretchability (4640%) and toughness (3.87×104 kJm-3 ). The resulting electrolyte demonstrates high ionic conductivity (1.41mScm-1 ), low interfacial resistance toward Li metal (48.1Ωcm2 ), and a wide electrochemical window (>4.8V vs Li+ /Li) at 30°C. Furthermore, the LiFePO4 /Li battery shows stable cycle performance with a capacity retention of 98.6% (146.3mAhg-1 ) over 1000 cycles at 1C (1C=170mAhg-1 ) at 30°C.

High figure-of-merit in Al-doped ZnO thin films grown by ALD through the Al content adjustment

The development of transparent conductive materials is of great interest for a wide variety of semiconducting devices in the fields of optoelectronics and photovoltaics. Here, we optimize the growth and properties of aluminum-doped ZnO (AZO) thin films as an eco-friendly transparent electrode by using atomic layer deposition (ALD) with diethylzinc (DEZn), water vapor and trimethylaluminium (TMA) as zinc, oxygen, and aluminum chemical precursors, respectively. The cycle ratio of DEZn to TMA using ALD is adjusted to control the Al atomic concentration over a broad range of 0.3 - 6.7% while optimizing the structural, optical, and electrical properties of AZO thin films. By incorporating a sufficient amount of Al dopants around 1.1%, we obtain a high quality AZO thin film exhibiting a low electrical resistivity of 6.3 × 10−4 Ω·cm. This AZO thin film grown on quartz substrate also demonstrates an average optical transmittance in the visible range above 85% as well as a high figure-of-merit of 6.4 × 10−3 Ω−1, while maintaining its highly c-axis oriented structure. The present optical and electrical properties result in the fabrication of AZO thin films by ALD with a high figure-of-merit that is highly suitable for many semiconducting devices.

Performance of multifunctional antibacterial moisture barrier films with different Zn/Al ratios fabricated by plasma enhanced atomic layer deposition

This study investigated Zn–Al composite oxide-based antibacterial moisture barrier film for flexible electronic devices using PEALD. Diethyl zinc and trimethyl aluminium precursors were used to deposit Zn and Al atoms, respectively, which were oxidised using oxygen plasma. The transmittance, refractive index, and water vapour transmission rate (WVTR), as well as the antibacterial and antifungal properties of the Zn–Al composite oxide thin films with different Zn/Al ratios were evaluated comparatively. The deposited films exhibited a linear change in refractive index from 1.66 to 1.87 and transmittance from 87.8 to 78.3% with an increase in the Zn ratio from 24.7 to 100. Furthermore, the film with a Zn ratio of 10.4 showed the best WVTR of 9.06 × 10−4 g/m2/day. In addition, the antibacterial and antifungal properties of the Zn–Al composite oxide thin films were evaluated through antibacterial and mould growth tests, respectively. All samples exhibited high antibacterial activities of 6.2 and 4.7 against Escherichia coli and Staphylococcus aureus, respectively, and no mould growth occurred on the surfaces of the Zn–Al composite oxide films. The antibacterial moisture-barrier films developed in this study can apply such as protecting human health, next-generation flexible touch displays and functional optical films.

Atomic Layer Deposition of Boron‐Doped Al2O3 Dielectric Films

AbstractThis paper presents preparation of boron‐doped Al2O3 thin films by atomic layer deposition (ALD) using phenylboronic acid (PBA) and trimethylaluminum (TMA) as precursors. Deposition temperatures of 160–300 °C are studied, giving a maximum growth per cycle (GPC) of 0.77 Å at 200 °C. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) are used to study the surface morphology and roughness of the films. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), Time‐of‐flight elastic recoil detection analysis (ToF‐ERDA), and X‐ray photoelectron spectroscopy (XPS) are used to study the composition of the films. An annealing process is carried out at 450 °C for 1 h to investigate its effect on the elemental composition and electrical properties of the boron‐doped Al2O3 thin films. The boron‐doped Al2O3 70 nm thick film deposited at 200 °C has a boron content of 3.7 at.% with low leakage current density (10−9 to 10−6 A cm−2) when the film thickness is 70 nm. The dielectric constant of this boron doped Al2O3 film is 5.18.

Passivation capping of InAs surface quantum dots by TMA/Al2O3: PL enhancement and blueshift suppression

Passivation capping that enhances the photoluminescence (PL) of molecular beam epitaxy (MBE)-grown InAs surface quantum dots (SQDs) is realized by ex situ low-temperature atomic layer deposition (ALD)-grown Al2O3. As the Al2O3 cap thickness increased from 2 to 30 nm, the PL intensity was enhanced by 2.7-fold and the blue shift was suppressed. This is in strong contrast to wet chemistry passivation and in situ GaAs capping by MBE, both of which resulted in significant PL blueshift, due to etching in the former, and In/Ga intermixing and strain in the latter. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) reveal that the Al2O3 cap layer mimics the shape of the underlying SQDs. The cross-sectional transmission electron microscopy (TEM) further reveals that the SQD size and shape remained unchanged after Al2O3 capping, which is in strong contrast to MBE-capping. The passivation mechanisms and native oxide reduction by trimethylaluminum (TMA), including self-clean-up reaction through ligand exchange, are discussed based on the results by x-ray photoelectron spectroscopy (XPS). A detailed comparison between Al2O3 and ZnO cap layers reveals the significance of the cap properties on the SQD size/shape and PL blueshift. While the size/shape of SQDs is preserved by Al2O3 capping, the apex is slightly removed by ZnO capping, resulting in a stronger PL blueshift compared to Al2O3.

Limiting reagent conditions to control inorganic loading in AlOx–PET hybrid fabrics created through vapor-phase infiltration

In this work, the vapor-phase infiltration (VPI) of polyethylene terephthalate (PET) fabrics with trimethylaluminum (TMA) and coreaction with water vapor is explored as a function of limiting TMA reagent conditions versus excess TMA reagent conditions at two infiltration temperatures. TMA is found to sorb rapidly into PET fibers, with a significant pressure drop occurring within seconds of TMA exposure. When large quantities of polymer are placed within the chamber, minimal residual precursor remains at the end of the pressure drop. This rapid and complete sorption facilitates the control of inorganic loading by purposely delivering a limited quantity of the TMA reagent. The inorganic loading for this system scales linearly with a Precursor:C=O molar ratio of up to 0.35 at 140 °C and 0.5 at 80 °C. After this point, inorganic loading is constant irrespective of the amount of additional TMA reagent supplied. The SEM analysis of pyrolyzed hybrids indicates that this is likely due to the formation of an impermeable layer to subsequent infiltration as the core of the fibers remains uninfiltrated. The Precursor:C=O molar ratio in the subsaturation regime is found to tune the hybrid fabric morphology and material properties such as the optical properties of the fabric. Overall, this work demonstrates how a reagent-limited processing route can control the inorganic loading in VPI synthesized hybrid materials in a simpler manner than trying to control kinetics-driven methods.

Chemical modification of carbon edge sites using trimethylaluminum to enhance the oxidation resistance of carbon materials

As the oxidation of carbon materials proceeds from chemically reactive carbon edge sites, increasing the chemical stability of carbon edge sites is expected to increase the oxidation resistance. In this study, we developed a method for enhancing the chemical stability of carbon materials by modifying the carbon edge sites with chemically stable metal oxides. We focused on aluminol as a potentially stable metal oxide and introduced it to the carbon edge sites by modifying them with trimethylaluminum (TMA). Moreover, we investigated the effect of this introduction on the electrochemical oxidation resistance of the carbon material. A detailed structural analysis of the TMA-treated carbon samples indicated that TMA reacts one-to-one with the hydroxyl groups at the edge sites and modifies them with aluminol. An investigation of the effect of TMA treatment on the electrochemical oxidation resistance of carbon samples revealed that TMA treatment increases the oxidation resistance only when the ratio of TMA-modified sites to total carbon edge sites is ≥ 60%.

Atomic layer deposition of α-Al2O3 from trimethylaluminum and H2O: Effect of process parameters and plasma excitation on structure development

Aluminum oxide (Al2O3) thin films were deposited from trimethylaluminum (TMA) and H2O on Si substrates and α-Cr2O3 seed layers using thermal and plasma-assisted atomic layer deposition (ALD). All films deposited on Si were amorphous. On the α-Cr2O3 seed layers, α-Al2O3 was formed at temperatures ≥350 °C in the thermal ALD and at ≥325 °C in the plasma-assisted ALD processes. The Ar plasma used in the experiments most significantly contributed to crystallization when applied during the purge period following the H2O pulse or during the H2O pulse and the following purge. Application of plasma during the TMA pulse, during the purge following the TMA pulse, or only during the H2O pulse suppressed the crystal growth and could potentially be applied as a crystal growth inhibitor.

Comprehensive Study of the Chemical, Physical, and Structural Evolution of Molecular Layer Deposited Alucone Films during Thermal Processing

Thermal processing of molecular layer deposited (MLD) hybrid inorganic–organic alucone thin films produced porous and low-k materials. Alucone films were deposited by MLD using trimethyl aluminum and ethylene glycol at 120 °C. Changes in the film density and thickness during annealing were monitored using in-situ X-ray reflectivity and were compared to atomic layer deposited (ALD) alumina films. The chemical evolution of the as-deposited and annealed alucone films during post-deposition heating with and without UV was probed using infrared spectroscopy, Rutherford backscattering, nuclear reaction analysis, and 15N spectroscopy, providing a detailed understanding of the induced changes. The concentration of OH groups decreased after depositing 1 nm of alumina capping layer as a barrier to moisture uptake, which also decreased the etch rate in CF4/O2 plasma. The lowest dielectric constant of the processed alucone films (kmin = 4.75) was 25% lower than the lowest values measured in ALD alumina counterparts (kmin = 6.7). Large thickness decreases for alucone films were observed at ∼200 °C of anneal temperatures. Removal of retained organic components by thermal processing of MLD films is demonstrated to be a promising and versatile route to porous thin films for a wide range of applications including low dielectric constant materials.

Inherent selective pulsed chemical vapor deposition of aluminum oxide in nm scale

Inherent selective pulsed chemical vapor deposition (CVD) of aluminum oxide on Si and SiO2 in preference to SiCOH has been studied. SiCOH is alkyl (-CxHy) terminated SiO2, which was used as a non-reactive surface. For aluminum oxide deposition, pulsed CVD processes using aluminum tri sec-butoxide (ATSB) and trimethylaluminum (TMA) were tested. ATSB alone can induce a pulsed thermal CVD reaction to selectively deposit aluminum oxide at 300 °C sample temperature; ∼4 nm of aluminum oxide were selectively deposited on Si and SiO2 in preference to SiCOH. By adding a periodical pulse of TMA during ATSB pulses, higher selectivity was achieved with ∼12 nm and ∼14 nm of aluminum oxide on Si and SiO2 with around 0.4–0.5 nm root mean square (RMS) roughness at 330 °C. The high selectivity persisted on the nanoscale: STEM showed that ∼10 nm of aluminum oxide could be selectively deposited on nanoscale patterned features. The selectively deposited AlOx films showed low k (∼4) dielectric performance with low leakage (around 10−6 A/cm2 at ± 2 V for a 15 nm thick film). This selective aluminum oxide pulsed CVD process has the potential to be applicable in nanoscale fabrication, such as low k spacer and etch stop layer.

Preserved subsurface morphology in NIPS and VIPS laser-induced graphene membranes affects electrically-dependent microbial decontamination

Laser-induced graphene (LIG) is a graphitic material that can be easily formed by CO2-laser irradiation on a variety of carbon-based substrates, including porous polymeric membranes. LIG-membrane formation involves lasing the top surface of a polymeric membrane, and converts essential polymer separation structures to porous LIG foam. However, in previous studies, separation properties could be partly recovered by forming LIG polymer composite layers or by coating the polymeric membrane substrate with trimethylaluminum (TMA) or graphene oxide (GO) to avoid melting or damaging the membrane pore structure and the subsurface polymeric structures during the lasing process. Herein, by optimizing the laser settings and fabrication conditions, we made LIG directly on uncoated porous PES membranes, while preserving the subsurface polymer. The effects of lasing on membrane properties were studied by comparing porous polymeric PES membranes fabricated using the non-solvent induced phase separation (NIPS) or the vapor-induced phase separation (VIPS) method. Membrane fabrication conditions such as the polymer concentration of the casting solution and the exposure time to the non-solvent were varied, and the NIPS method resulted in membranes with a finger-like polymer substructure morphology while the VIPS method resulted in membranes with an asymmetric cellular morphology. LIG-membranes prepared on NIPS membranes resulted in large permeability changes, while LIG on VIPS membranes gave only very minor changes. The antimicrobial activity of these LIG-membranes as porous electrodes was dependent on applied voltage and solution contact time and 4–6 log removal of bacteria at 10 V was achieved. Understanding LIG formation on porous polymeric membranes will minimize processing steps and might lead to electrically conductive membranes with controlled separation properties.

In vacuo cluster tool for studying reaction mechanisms in atomic layer deposition and atomic layer etching processes

In this paper, we introduce a vacuum cluster tool designed specifically for studying reaction mechanisms in atomic layer deposition (ALD) and atomic layer etching (ALE) processes. In the tool, a commercial flow-type ALD reactor is in vacuo connected to a set of UHV chambers so that versatile surface characterization is possible without breaking the vacuum environment. This way the surface composition and reaction intermediates formed during the precursor or etchant pulses can be studied in very close to true ALD and ALE processing conditions. Measurements done at each step of the deposition or etching cycle add important insights about the overall reaction mechanisms. Herein, we describe the tool and its working principles in detail and verify the equipment by presenting results on the well-known trimethyl aluminum–water process for depositing Al2O3.

Incorporating Binary Metal Oxides in Poly(ethylene oxide)-Based Solid Electrolytes by Vapor Phase Infiltration

Vapor phase infiltration (VPI) derived from atomic layer deposition (ALD) enables inorganic materials to nucleate and grow within the free volume of polymers, which has shown promising prospects in the field of composite solid polymer electrolytes (CSPEs). However, there are only a few types of metal oxides that can be incorporated into the polymer matrix by VPI, let alone binary metal oxides, due to the limited knowledge of the VPI synthesis process. To combine the merits of different metal oxides, we investigate the VPI method to prepare ZnO-Al2O3 composites in poly(ethylene oxide) (PEO). When the introducing order is Al2O3/ZnO (AZO), due to the extremely high reactivity of trimethyl aluminum (TMA) with PEO, VPI-Al2O3 will accumulate near the surface of PEO. The surface Al2O3 layer inhibits the further diffusion of the diethyl zinc (DEZ) into the PEO matrix, leading to weak polymer-filler interactions and limited improvement of the Li+ conduction. In the incorporation order of ZnO/Al2O3 (ZAO), the moderate reactivity of DEZ renders the uniform distribution of VPI-ZnO within PEO, and the following TMA can both react with PEO and VPI-ZnO particles near the surface of PEO, which not only preserves the interactions between VPI-ZnO and PEO but also better inhibits the growth of lithium dendrites. The incorporation order plays a crucial role in the morphology and composition of binary metal oxides synthesized by VPI.