Etching characteristics and surface properties of fluorine-doped tin oxide thin films under CF4-based plasma treatment

Abstract

Owing to their low-cost, high-temperature processability, and excellent optoelectronic properties, fluorine-doped tin oxide (FTO) films are widely used as transparent conductive materials to replace indium-tin-oxide films. Dry etching is increasingly preferred for the patterning of FTO films considering the high-resolution patterning process required for microdevice applications. This study investigates the dry etching of FTO thin films using CF4-based plasma treatment and analyzes the changes in the etching characteristics and surface properties based on various conditions. The highest etching rate was observed under pure CF4 conditions, indicating that the chemical etching effect is the primary mechanism during the etching process. Based on the X-ray photoelectron spectroscopy and optical emission spectroscopy results, we determined that the etching of the FTO thin film was caused by the CFX radical in the CF4based plasma. Additionally, the X-ray diffraction results indicate that the plasma etching increased the crystal defects in the FTO film. The etching process smoothened the surface morphology of the FTO film, and the transmittance and bandgap energy were slightly changed as a function of the etching conditions. Additionally, the resistivity of the FTO film improved slightly. The obtained results can benefit the development of high-performance optical devices that use FTO as transparent electrodes.

Etching characteristics and surface modification of InGaSnO thin films under Cl2/Ar plasma

“…Figure 2 reveals that as the flow rate of Cl 2 increases from 0 to 100 sccm, the etch rate of the IGTO thin film increases from 9 to 69 nm min −1 . This result indicates that the chemical reaction with Cl or Cl 2 radicals rather than the physical reaction with Ar ions is the primary etching mechanism in the etching of the IGTO thin film [21,22]. When the IGTO thin film is etched using Cl 2 /Ar mixed gas, the by-products generated on the surface of the IGTO thin film are a combination of Cl and metals such as InCl x , GaCl x , and SnCl x .…”

Observing Metallic Carriers in Highly Faceted Plasmonic Cd2SnO4 Inverse Spinel Nanocrystals

“…[7][8][9][10][11] MO x PSNCs are an important class of n-type plasmonic materials shown to exhibit high conductivity and mobility in thin films and form the basis of transparent conducting oxide industrial technology. [12][13][14][15][16][17] The LSPR frequencies of MO x PSNCs are predictable using dielectric modeling of the carrier effective mass (m * ), carrier density (n), band parabolicity, and degree of compensation centers arising from lattice defects. [8,[18][19][20][21][22][23][24] The most heavily studied n-type MO x s rely on oxygen vacancies (V O ) to induce carriers in the conduction band (CB); however, the presence of V O 's is associated with rapid carrier trapping following LSPR excitation in PSNCs.…”