Crystallization behavior during transparent In₂O₃‐ZnO film growth

Abstract

Structural evolution of transparent conductive In 2 O 3 -ZnO (IZO) films with increasing substrate temperature during sputtering was studied using transmission electron microscopy (TEM) and spectroscopic ellipsometry. Increasing the substrate temperature can induce film crystallization in the initial growth stage, and enhance the crystallization of IZO films. Extensive simulations using ellipsometry data demonstrated a decrease in the crystallization rate for IZO films deposited between 200 and 300• C, which is attributed to the influence of the interference between nearby growing grains. TEM observations also reveal that the growth competition between different crystallites leads to an increase in the lateral grain size with increasing substrate temperature. During physical vapor deposition, crystallization often starts from an amorphous matrix, and then grows to form the polycrystalline film with a typical columnar structure. Such a transformation in the crystal structure can be attributed to the effect of deposition rate and surface diffusion [6]. Currently, there is a demand for experimental confirmation and direct observation of such structural evolution. In this study, spectroscopic ellipsometry (SE) was explored to study the crystallization transformation arising from surface diffusion.The SE technique does not determine sample properties directly, but rather measures the ratio of complex reflectances for s-and p-polarized light, which is changed to

On the Crystal Structural Control of Sputtered TiO2 Thin Films

“…4. The sketch images demonstrate that many small crystallites were formed on the substrate in the initial growth stage and that these crystallites gradually decreased in number and increased in grain size with increasing film thickness; we attributed this behaviour to the growth competition among the crystallites [24]. The Debye-Scherrer rings in the electron diffraction patterns (inset in Fig.…”

Temporal Evolution of Microscopic Structure and Functionality during Crystallization of Amorphous Indium-Based Oxide Films

“…Such requirements are satisfied by indium-based functional amorphous oxide films . For example, amorphous In 2 O 3 and amorphous indium–tin oxide (a-ITO) are used as transparent conductive oxide (TCO) materials in flexible thin film displays, , and amorphous indium–gallium oxide (a-IGO) and amorphous indium–gallium–zinc oxide (a-IGZO) are exploited as active semiconductor channel materials in flexible thin film transistors (TFTs). , With no grain boundaries and internal stresses, these materials exhibit superior uniformity and smoothness, flexibility, and corrosion resistance. Moreover, the carrier density of indium-based amorphous oxide films can be controlled over a wide range (10 × 10 14 –10 × 10 21 cm –3 ), , enabling wide-ranging electrical functionality (semiconducting to conducting) for a variety of high-tech flexible device applications.…”

“…4 Such requirements are satisfied by indium-based functional amorphous oxide films. 5 For example, amorphous In 2 O 3 and amorphous indium−tin oxide (a-ITO) are used as transparent conductive oxide (TCO) materials in flexible thin film displays, 5,6 and amorphous indium−gallium oxide (a-IGO) and amorphous indium−gallium−zinc oxide (a-IGZO) are exploited as active semiconductor channel materials in flexible thin film transistors (TFTs). 7,8 With no grain boundaries and internal stresses, these materials exhibit superior uniformity and smoothness, flexibility, and corrosion resistance.…”

“…7,8 With no grain boundaries and internal stresses, these materials exhibit superior uniformity and smoothness, flexibility, and corrosion resistance. Moreover, the carrier density of indium-based amorphous oxide films can be controlled over a wide range (10 × 10 14 −10 × 10 21 cm −3 ), 6,9 enabling wide-ranging electrical functionality (semiconducting to conducting) for a variety of high-tech flexible device applications.…”

High-mobility and high-reliability Zn-incorporated amorphous In2O3-based thin-film transistors

“…In the In-rich area, the Zn ratio of 9% Zn films is well consistent with the reported crystallization of Zn ratio <16 wt%. 24,25) Subsequently, we measured the electron transport properties of the IZO films. Figure 3 shows changes in carrier concentration (n), Hall mobility (μ Hall ), and thermopower (S) as a function of Zn concentration in the IZO films.…”