Transparent Indium Gallium Zinc Oxide Research Articles

High Performance and High Yield Solution Processed IGZO Thin Film Transistors Fabricated with Low‐Temperature Annealed Hafnium Dioxide Gate Dielectric

AbstractSolution‐processed microelectronics offer advantages, including cost‐effectiveness, higher energy efficiency, and compatibility with rapid prototyping compared to their counterparts fabricated through traditional semiconductor manufacturing processes. Unfortunately, solution‐processed transistors exhibit wide performance variability and low yield. In this work, a solution‐processed transparent indium gallium zinc oxide (IGZO) thin film transistor with a low temperature‐annealed hafnium oxide dielectric layer is described. Post‐annealing temperatures for the sol–gel hafnium dioxide thin film are reduced to below 200 °C, significantly expanding the range of substrates on which the metal oxide dielectric can be deposited. The fabricated devices exhibit excellent characteristics with high field‐effect mobilities of over 85 cm2 V−1 s−1, along with low subthreshold swing below 140 mV dec−1, high on/off ratios, and near‐zero threshold voltages when operating stably at low‐operating voltages of 2 V. The solution processed transparent hafnium dioxide gate dielectric IGZO transistors are shown to exhibit comparatively significantly lower device variation and high yield, allowing for the reproducible fabrication of large‐area and transparent solution processed microelectronics systems.

Bulk preparation of transparent IGZO TFTs with CS gate dielectric as glucose sensor on a pilot line

In this paper, the indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) with chitosan (CS) gate dielectric are prepared by the conventional photolithography technique on a pilot line. As-prepared devices on 200 × 200 mm substrate is very uniform, and have good performance of high on/off drain current ratio ~ 10−6, low subthreshold swing ~ 0.24, low-threshold voltage ~ 0.20 V and high-visible light transmittance > 90%. The glucose oxidase is drop-cased on the CS gate dielectric surfaces to make fully transparent CS-based IGZO TFTs with sensitivity to glucose. It is found that the current noticeably changes with increasing glucose concentrations. Herein, the glucose detection range from 0.5 to 30 mM covers the normal range of human blood glucose concentration. Moreover, the response time for glucose sensing is < 10 s, which is effective in detecting glucose. The results suggest that the CS-based IGZO TFTs can be used to detect glucose and provides a simple process to achieve low-cost- and larger-area fabrication of biosensors.

Highly Transparent, Visible-Light Photodetector Based on Oxide Semiconductors and Quantum Dots.

Highly transparent phototransistors that can detect visible light have been fabricated by combining indium-gallium-zinc oxide (IGZO) and quantum dots (QDs). A wide-band-gap IGZO film was used as a transparent semiconducting channel, while small-band-gap QDs were adopted to absorb and convert visible light to an electrical signal. Typical IGZO thin-film transistors (TFTs) did not show a photocurrent with illumination of visible light. However, IGZO TFTs decorated with QDs showed enhanced photocurrent upon exposure to visible light. The device showed a responsivity of 1.35×10(4) A/W and an external quantum efficiency of 2.59×10(4) under illumination by a 635 nm laser. The origin of the increased photocurrent in the visible light was the small band gap of the QDs combined with the transparent IGZO films. Therefore, transparent phototransistors based on IGZO and QDs were fabricated and characterized in detail. The result is relevant for the development of highly transparent photodetectors that can detect visible light.

UV Sensitive Indium Gallium Zinc Oxide MOS- FET Fabricated by RF Magnetron Sputtering Method

Transparent indium gallium zinc oxide (IGZO) thin film was fabricated on SiO2/Si substrate by radio-frequency magnetron sputtering method. The IGZO thin film was characterized by X-ray diffraction, UV-VIS spectrometer, X-ray photoelectron energy spectrum to determine its optical, structural properties and binding energy information. The IGZO thin film was employed to construct metal-oxide-semiconductor field effect transistors (MOS-FET), which showed an on/off current of about 103. When the device was illuminated by UV light, the drain-to-source current was increased by 15 folders at -5 V gate voltages. The result indicates that the IGZO MOS-FET is sensitive to UV light.

Transparent indium gallium zinc oxide transistor based floating gate memory with platinum nanoparticles in the gate dielectric

A transparent memory device has been developed based on an indium gallium zinc oxide thin film transistor by incorporating platinum nanoparticles in the gate dielectric stack as the charge storage medium. The transfer characteristics of the device show a large clockwise hysteresis due to electron trapping and are attributed to the platinum nanoparticles. Effect of the gate bias stress (program voltage) magnitude, duration, and polarity on the memory window characteristics has been studied. Charge retention measurements were carried out and a loss of less than 25% of the trapped elec-trons was observed over 104 s indicating promising application as nonvolatile memory.