In2O3-ZnO sputtering target

Abstract

A sputtering target that comprises an oxide containing indium, zinc, and at least one element (X) selected from group X, with the atomic ratios between said elements satisfying relations (1) and (2). Group X: magnesium, silicon, aluminum, scandium, titanium, yttrium, zirconium, hafnium, tantalum, lanthanum, neodymium, and samarium, (1) In / (In+Zn) is more than or equal to 0.30 and less than or equal to 0.90, and (2) In / (In+X) is more than or equal to 0.70 and less than or equal to 0.99 (In these relations, In, Zn, and X represent the atomic ratios of indium, zinc, and element X in the sputtering target, respectively.).

Description

technical field [0001] The present invention relates to a sputtering target for producing oxide thin films such as oxide semiconductors and transparent conductive films, and particularly relates to a sputtering target suitable for forming oxide thin films for thin film transistors. Background technique [0002] Field-effect transistors are widely used as unit electronic elements of semiconductor memory integrated circuits, high-frequency signal amplification elements, liquid crystal drive elements, and the like, and are currently the most practical electronic devices. Among them, with the development of display devices in recent years, not only in liquid crystal display devices (LCD), but also in various display devices such as electroluminescent display devices (EL) and field emission displays (FED), thin-film transistors ( TFT) as a switching element that drives a display device by applying a driving voltage to the display element. [0003] Among TFT drive elements, silic...

AI Technical Summary

Problems solved by technology

However, when the film is formed by the sputtering method generally performed in industry, the oxide semiconductor film containing a crystalline substance mainly composed of zinc oxide has the following problems: it is easy to generate oxygen vacancies, a large number of carriers are generated, and it is difficult to use The conductivity becomes smaller

In addition, when forming a film by the sputtering method, there are problems that abnormal discharge occurs, the stability of film formation is impaired, and the uniformity and reproducibility of the obtained film are lowered.

[0005] In addition, in particular, for an oxide semiconductor film containing a crystalline substance mainly composed of zinc oxide, the field-effect mobility (hereinafter sometimes simply referred to as "mobility") is as low as 1 cm 2 About / V sec, the on / off ratio is small, and it is easy to generate leakage current

Therefore, when an oxide semiconductor film containing a crystalline substance mainly composed of zinc oxide is used as the active layer (channel layer) of the TFT, there is a problem that a large current flows even when no gate voltage is applied. Between the source terminal and the drain terminal, so that the normally-off (normally-off) operation of the TFT cannot be achieved

However, there are problems as follows: Gallium is a rare metal and the cost of raw materials is high. If the amount of gallium added is reduced or the oxygen partial pressure during film formation is not increased, the normally-off operation of TFT cannot be realized.

However, this target has the following problems: it is easy to form aggregates of insulating substances, which increases the resistance value, and it is easy to cause abnormal discharge, etc.

Images