GaZnO Thin Films Research Articles

Properties of In–Ga–Zn-O thin films for thin film transistor channel layer prepared by facing targets sputtering method

Amorphous indium–gallium–zinc-oxide (a-IGZO) thin films were prepared using the facing targets sputtering (FTS) method as a function of input power at room temperature. The a-IGZO films were used a channel layer for thin film transistors (TFTs). The electrical, optical, and structural properties of a-IGZO thin films were measured by Hall Effect measurement, UV/vis spectrometer and X-ray diffractometer. The performance and device characteristics of the a-IGZO TFTs were measured by using a semiconductor parameter analyzer. The transfer characteristics of a-IGZO TFTs exhibited saturation mobility of 10.83 cm 2/V s and threshold voltage of 5.13 V.

Etching characteristics and mechanism of Ga-doped ZnO thin films in inductively-coupled HBr/ X ( X = Ar, He, N 2, O 2) plasmas

We investigated the etch characteristics and mechanisms of Ga-doped ZnO (Ga–ZnO) thin films in HBr/ X ( X = Ar, He, N 2, O 2) inductively-coupled plasmas. The etch rates of Ga–ZnO thin films were measured as a function of the additive gas fraction in the range of 0–100% for Ar, He, N 2, and O 2 at a fixed gas pressure (6 mTorr), input power (700 W), bias power (200 W), and total gas flow rate (40 sccm). The plasma chemistry was analyzed using a combination of the global (zero-dimensional) plasma model and Langmuir probe diagnostics. By comparing the behavior of the etch rate and fluxes of plasma active species, we found that the Ga–ZnO etch process was not limited by ion-surface interaction kinetics and appeared in the reaction rate-limited etch regime. In the HBr/O 2 plasma, the etch kinetics were probably influenced by oxidation of the etched surface.

Bandgap-Engineered Ga-Rich GaZnO Thin Films for UV Transparent Electronics

Ga-rich GaZnO thin films were prepared by metal-organic chemical vapor deposition. The optical bandgap of GaZnO films can be engineered from 3.3 to 4.9 eV by varying the Ga content. The film is amorphortized and the resistivity increases with an increase of Ga content. The Ga-rich GaZnO alloy with lower resistivity is investigated as a UV transparent conductor, while the semi-insulating Ga-rich GaZnO film with high transparency at 280-900 nm is employed as the channel layer to fabricate deep UV transparent thin-film transistor. The transistor shows a typical n-channel field-effect characteristic with a current on/off ratio of 104 - 105, a threshold voltage of ~42 V, a saturated field-effect mobility of ~0.06 cm2 middot V-1 middot s-1, and a subthreshold swing of ~7.7 V middot decade-1.