Roll‐to‐Roll Atmospheric Atomic Layer Deposition of Al₂O₃ Thin Films on PET Substrates

Abstract

The conventional atomic layer deposition (ALD) technologies are capable of fabricating supreme quality thin films of a wide variety of materials, but sequential introduction and purging of precursors and inert gases prevent its application in the mass production of thin films under atmospheric conditions. In this study, we introduce a novel technique of roll-to-roll atmospheric (R2R-A)ALD using a multiple-slit gas source head. Thin films of Al 2 O 3 are developed on a movable web of polyethylene terephthalate (PET) substrate at 50°C. The Al 2 O 3 deposition is carried out under a working pressure of 740 Torr, which is very near to atmospheric pressure (760 Torr). An appreciable growth rate of 0.98 A per cycle is observed at a carefully optimized web velocity of 7 mm s À1 . Good morphological, chemical, electrical, and optical characteristics are shown by the Al 2 O 3 films produced at a large scale. Low root mean square roughness (R q ) values of 1.85 nm and 1.75 nm are recorded for the Al 2 O 3 films deposited at 50°C over 75 and 125 ALD cycles, respectively. The appearance of Al 2p, Al 2s, and O 1s peaks at the binding energies of 74 eV, 119 eV, and 531 eV, respectively, in the X-ray photoelectron spectroscopy (XPS) analysis confirms the fabrication of Al 2 O 3 films, which is also supported by Fourier transform infrared spectroscopy (FTIR). The films show excellent insulating properties, and optical transmittance of more than 85% is recorded in the visible region.

Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

“…While industry versions of these reactors have the advantages of operating sheet-to-sheet and in-line with other processes, 6 fully realizing the high throughput potential of AP-SALD will likely require R2R processing. 5 Prototypes of these reactors have started to appear, 34,43,47 mainly for Al 2 O 3 deposition. The knowledge generated on AP-SALD ZnO (intrinsic and doped) using the reactors shown in Sec.…”

“…31 It is important to avoid gas intermixing, since this results in chemical vapor deposition (CVD). 33,34 Inert carrier gas (e.g., N 2 ) is bubbled through the liquid organometallic metal precursor(s) and oxidant (H 2 O). The vapors of the metal precursor(s), oxidant, and the inert gas are separately fed to the gas manifold.…”

“…23,25,26,36 The low temperatures are compatible with some industrial polymer substrates, which for AP-SALD enable the process to be compatible with atmospheric pressure, roll-to-roll (R2R) deposition of ZnO onto continuous substrates (e.g., polymers, foil, or paper). 23,34,37,38 AP-SALD ZnO was first reported by Levy et al 16 Their reactor was further developed by Cambridge University and used to produce Cu 2 O, 35 TiO 2 , 24 and doped and intrinsic ZnO. 18,23,25,26,28,36,39 Various names have been given to describe this system, but in this research update, we standardize its name to the Cambridge University Close Proximity (CUCP) reactor (design details are given in Ref.…”

Slot-Die Coated Active Carbon Films for Hydrogen Storage Applications

“…The details of the roll-to-roll continuous slot-die manufacturing process can be found elsewhere [11,12]. Simplified two-dimensional (2D) simulations of the process were carried out to obtain the most suitable coating parameters as to achieve films with thickness of 3-8 µm.…”

P‐77: Area‐Selective Atomic Layer Deposition Using Inkjet‐printed Fluorocarbon Patterns as Mask Layers

“…After FC mask layer patterning, the glass substrates were placed on a hot plate at 110 ℃ for 10 min to bake the printed FC mask patterns. Al2O3 was deposited on the glass substrates with the printed FC mask patterns for ~ 4 nm target thickness using the multiple-slit ALD equipment (Figure 1(b)) [18]. Then, the unwanted FC mask patterns were removed with an O2 plasma system (Jesagi hankook, JSPCS-300) (Figure 1…”