Room-temperature growth of crystalline indium tin oxide films on glass using low-energy oxygen-ion-beam assisted deposition

Abstract

One of the long-standing problems to improve the resolution of organic electroluminescence devices has been related to the fabrication of very smooth, high-quality indium tin oxide (ITO) layers at room temperature. It seems that this problem could be solved by low-energy oxygen-ion-beam assisted electron-beam evaporation of ITO bulk material in vacuum. The oxygen ions were produced in an electron cyclotron resonance source with energies varied between 50 and 1000 eV. The growth rate changes from 0.04 to 0.23 nm/s. The structural, electrical and optical properties were characterized by x-ray diffraction, Rutherford backscattering, atomic force microscopy, Hall-effect and optical transmittance measurements. Crystalline structure, which depends only on the thickness of the deposited ITO films, can be easily obtained at room temperature. A very smooth surface of only 0.6 nm roughness (root mean square), almost one order smaller than that prepared by other methods, low resistivity of 7.0×10−4 Ω cm, high carrier density of 6.1×1020 cm−3, and high optical transmittance of 85% at wavelength 550 nm (including the glass substrate) could be repeatedly achieved at room temperature.

Structural and morphological properties of ITO thin films grown by magnetron sputtering

“…Furthermore, by increasing the thickness to 300 nm, additional diffraction peaks also appear, such as the formation of crystallites in the (2 1 1), (2 2 2), (4 0 0), (4 4 0) and (6 2 2) orientations with a preferred orientation still along the (2 2 2) direction. These data are in good agreement with the reported values [21]. The peak is verified to be the (2 2 2) peak of cubic bixbyite In 2 O 3 .…”

“…Various techniques, such as electron beam evaporation [7], ion beam-assisted deposition [8], pulsed laser ablation [9,10], ion implantation [11] and RF/DC magnetron sputtering [12][13][14], are applied for deposition of ITO thin films. Besides the process parameters, the thickness also can affect the properties of the samples [15][16][17][18][19][20][21][22].…”

Electronic conduction properties of indium tin oxide: single-particle and many-body transport

“…We do not cover insulating or amorphous ITO materials in this Topical Review, where the electronic conduction processes can be due to thermally excited hopping [58][59][60][61][62].…”

Room temperature deposition of crystalline indium tin oxide films by cesium-assisted magnetron sputtering

“…In particular, due to the low thermal stability of polymers [2], low temperature growth of ITO films has been a key issue in the field of flexible displays in which polymers must be used as substrate materials [2,3]. Therefore, the synthesis of ITO films with low resistivity and high transmittance has been recently pursued by many researchers at low temperature without dimensional change and thermal damage of polymers [4][5][6][7]. For the low temperature deposition of ITO films, diverse methods have been attempted such as ion beam-assisted deposition (IAD), pulse laser deposition with cluster ion beams, and DC or RF sputtering with substrate bias [4][5][6].…”

“…Therefore, the synthesis of ITO films with low resistivity and high transmittance has been recently pursued by many researchers at low temperature without dimensional change and thermal damage of polymers [4][5][6][7]. For the low temperature deposition of ITO films, diverse methods have been attempted such as ion beam-assisted deposition (IAD), pulse laser deposition with cluster ion beams, and DC or RF sputtering with substrate bias [4][5][6]. In case of an IAD technique, ion beams increase the mobility of surface adatoms by momentum transfer with energetic ions and then ITO films with smoother and denser structures can be obtained even at room temperature [4,7].…”