RADIATION-RESISTANT METAL OXIDE SEMICONDUCTOR COMPOSITION CONTAINING ZINC-INDIUM-TIN OXIDE, AND PREPARATION METHOD AND USE THEREOF

Abstract

The present invention relates to a radiation-resistant metal oxide semiconductor composition containing zinc-indium-tin oxide (ZITO) exhibiting radiation resistance, and a preparation method and use thereof. In the present invention, the radiation-resistant metal oxide semiconductor composition containing ZITO exhibiting radiation resistance is used in an electronic device for radiation exposure, which is used in outer space, nuclear power plants, or in spaces where medical or security devices are utilized by means of radiation, and thus, the damage caused by radiation can be prevented, thereby improving the electrical properties of the device (e.g., turn-on voltage (V.sub.on)), and the life-span and reliability thereof.

Claims

1. A radiation-resistant metal oxide semiconductor composition containing zinc-indium-tin oxide (ZITO) exhibiting radiation resistance.

2. The radiation-resistant metal oxide semiconductor composition of claim 1, wherein the ZITO is resistant to proton rays, gamma rays, and X-rays.

3. The radiation-resistant metal oxide semiconductor composition of claim 1, wherein the composition of ZITO for exhibiting radiation resistance is controlled within the range of Zn:In:Sn=4 to 2:1:1.

4. The radiation-resistant metal oxide semiconductor composition of claim 1, wherein the ZITO exhibiting radiation resistance forms a metal oxide semiconductor layer of a radiation-resistant electronic device.

5. The radiation-resistant metal oxide semiconductor composition of claim 1, wherein the ZITO exhibiting radiation resistance forms a metal oxide semiconductor layer of a radiation-resistant transistor.

6. The radiation-resistant metal oxide semiconductor composition of claim 1, wherein the composition is a radiation-resistant oxide semiconductor target formed by sintering ZITO.

7. A radiation-durable oxide thin film transistor (TFT) for radiation exposure, wherein a channel layer is formed of the radiation-resistant metal oxide semiconductor composition containing radiation-resistant ZITO of claim 1 in order to reduce performance degradation or malfunction when exposed to radiation.

8. A radiation-durable electronic device for radiation exposure, wherein a radiation-resistant metal oxide semiconductor layer is formed of the radiation-resistant metal oxide semiconductor composition containing radiation-resistant ZITO of claim 1 in order to reduce performance degradation or malfunction when exposed to radiation.

9. The radiation-durable electronic device for radiation exposure of claim 8, wherein the electronic device is used in outer space, nuclear power plants, or in spaces where medical or security devices are utilized by means of radiation.

10. The radiation-durable electronic device for radiation exposure of claim 8, wherein the electronic device is equipped with a radiation-durable transistor, in which a channel layer is formed of the radiation-resistant metal oxide semiconductor composition containing radiation-resistant ZITO of claim 1.

11. A method for preparing the radiation-resistant metal oxide semiconductor composition containing radiation-resistant ZITO of claim 1, comprising confirming the formation of oxygen vacancy or the degree thereof in a metal oxide semiconductor material or metal oxide semiconductor layer by irradiating protons to a ZITO-containing metal oxide semiconductor material having a specific composition ratio of Zn:In:Sn or a device fabricated using the same.

12. The method of claim 11, wherein the formation of oxygen vacancy or the degree thereof is confirmed by determining the amount of free electrons generated when oxygen vacancy exists in the metal oxide semiconductor material or metal oxide semiconductor layer to be analyzed.

13. The method of claim 11, wherein the formation of oxygen vacancy or the degree thereof is determined by analyzing electron spin resonance (ESR) peaks obtained from free electrons generated at the oxygen vacancy in the metal oxide semiconductor material through ESR before and after proton irradiation, and/or analyzing O vacancy peaks and/or M-OH peaks through X-ray photoelectron spectroscopy (XPS).

14. The method of claim 11, further comprising confirming the degree of turn-on voltage (V.sub.on) change before or after irradiation of proton rays, gamma rays, or X-rays after fabricating an oxide semiconductor TFT device, in which the ZITO-containing metal oxide semiconductor material to be analyzed is used as a channel layer.

15. The method of claim 11, further comprising determining the crystal structure and/or the contents of zinc (Zn), indium (In), and tin (Sn) of the ZITO-containing oxide semiconductor material to order to impart a desired degree of radiation resistance to the ZITO-containing oxide semiconductor material.

16. A method for evaluating the radiation durability of an electronic device fabricated using a ZITO-containing metal oxide semiconductor material, comprising confirming the formation of oxygen vacancy or the degree thereof in a metal oxide semiconductor layer by irradiating protons to an electronic device fabricated using a ZITO-containing metal oxide semiconductor material.

17. The method of claim 16, wherein the formation of oxygen vacancy or the degree thereof is confirmed by determining the amount of free electrons generated when oxygen vacancy exists in the metal oxide semiconductor material or metal oxide semiconductor layer to be analyzed.

18. The method of claim 16, wherein the formation of oxygen vacancy or the degree thereof is determined by analyzing ESR peaks obtained from free electrons generated at the oxygen vacancy in the metal oxide semiconductor material through electron spin resonance (ESR) before and after proton irradiation, or analyzing O vacancy peaks and/or M-OH peaks through X-ray photoelectron spectroscopy (XPS).

19. The method of claim 16, further comprising confirming the degree of turn-on voltage (V.sub.on) change before or after irradiation of proton rays, gamma rays, or X-rays after fabricating an oxide semiconductor TFT device, in which the ZITO-containing metal oxide semiconductor material to be analyzed is used as a channel layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0087] FIG. 1 shows a schematic diagram showing TFT using a ZITO semiconductor material as a channel layer, and proton irradiation to the device.

[0088] FIG. 2 shows the change in the properties of a) ZITO (8:1:1), (b) ZITO (6:1:1), (c) ZITO (4:1:1), and (d) ZITO (2:1:1) devices and the Vg-Id change in the ZITO semiconductor thin films according to the proton radiation dose before and after 5 MeV proton irradiation with radiation doses of 10.sup.13 and 10.sup.14 cm.sup.2.

[0089] FIG. 3 shows the Vg-Id change in GSZO (1:3:6, 1:2:7), GTO (4:6), and GITO (2:1:1), which are oxide-based TFTs used as a control, according to the proton radiation dose before and after 5 MeV proton irradiation with radiation doses of 10.sup.13 and 10.sup.14 cm.sup.2.

[0090] FIG. 4 shows the change in the properties of ZITO (2:1:1) device and the Vg-Id change in the ZITO semiconductor thin film according to gamma ray and X-ray irradiation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0091] Hereinafter, the present invention will be described in more detail by way of Examples. However, these Examples are given for illustrative purposes only, and the scope of the invention is not intended to be limited to or by these Examples.

Preparation Example 1

[0092] As shown in FIG. 1, TFTs using ZITO (8:1:1, 6:1:1, 4:1:1, 2:1:1)-based channel layers were fabricated through a solution process using a spin coating technique, which enables a large-scale coating with low cost, while using a heavily N-doped silicon wafer (n.sup.++-Si) as the gate voltage, and a thermally grown-300 nm SiO.sub.2 layer as the gate insulator.

[0093] In particular, the process of forming the ZITO-based channel layer is as follows:

[0094] After dissolving zinc acetate dihydrate, indium chloride, and tin chloride pentahydrate in 2-methoxyethanol to control the ZITO composition ratio, a spin coating precursor solution was prepared by adding ethanolamine as a stabilizer. In particular, the total molar concentration of the metals was 0.075 M. After subjecting the solution to spin coating, a thin film was formed by annealing at high temperature of about 400 C., which was then used as a channel layer.

Example 1: Changes in Properties of ZITO Devices According to Proton Irradiation

[0095] After irradiating 5 MeV protons to the TFT devices equipped with ZITO channel layers having various composition ratios fabricated in Preparation Example 1 with radiation doses of 10.sup.13 and 10.sup.14 cm.sup.2, the change in the properties of the TFT devices according to the proton irradiation was confirmed.

[0096] As shown in FIG. 2, ZITO-based thin film transistors showed superior stability against protons at all composition ratios of ZITO compared to other previously reported oxides (IGZO, ZnO, ZTO). In particular, ZITO (4:1:1) showed the highest stability among them. The on voltage (V.sub.on), threshold voltage (V.sub.th), and mobility (), which are parameters for evaluating the performance of transistors, were nearly changed until the radiation dose of 10.sup.14 cm.sup.2.

[0097] Meanwhile, as shown in FIG. 3, GSZO (1:3:6, 1:2:7), GTO (4:6), and GITO (2:1:1)-based thin film transistors used as a control exhibited proton resistance significantly lower than ZITO (4:1:1). When the on voltage (V.sub.on), threshold voltage (V.sub.th) and mobility (), which are parameters for evaluating the performance of transistors were measured, it was confirmed that the on voltage (V.sub.on) and the threshold voltage (V.sub.th) of GSZO (1:3:6, 1:2:7) and GITO (2:1:1) increased in the negative direction from the radiation dose of 10.sup.13 cm.sup.2 and became fully conducted at the radiation dose of 10.sup.14 cm.sup.2. It seemed that GTO (4:6) was slightly more stable than GSZO and GITO, but the on voltage (V.sub.on) was shifted by about 40 V in the negative direction at the radiation of dose of 10.sup.14 cm.sup.2, confirming that the radiation resistance was remarkably reduced compared to ZITO (4:1:1).

Example 2: Changes in Properties of ZITO Devices According to Gamma Irradiation

[0098] The electrical stability of the devices was confirmed by irradiating 1 MeV gamma rays with radiation dose of 10M rad (100 Kgy) and 10 MeV X-rays with radiation dose of 10 Kgy to the TFT devices equipped with ZITO channel layers having various composition ratios fabricated in Preparation Example 1.

[0099] As shown in FIG. 4, in particular, the ZITO (2:1:1)-based thin film transistor showed excellent stability against gamma and X-rays. When the gamma rays were irradiated to the level of 10 Mrad, there was a slight decrease in mobility from 9 cm.sup.2/Vs to 6.6 cm.sup.2/Vs, and the on voltage and threshold voltage were shifted by about 4 V. Additionally, when the x-rays were irradiated to the level of 10 Kgy, it was confirmed that there was almost no change in the mobility and the threshold voltage.