TWI531009B - Oxide-type semiconductor material and sputtering target - Google Patents

Description

Oxide semiconductor materials and sputtering targets

The present invention relates to a semiconductor material for forming a semiconductor element constituting a display device such as a liquid crystal display, and more particularly to an oxide type semiconductor material containing a Zn oxide and a Sn oxide.

In recent years, display devices such as thin televisions, which are represented by liquid crystal displays, tend to have an increase in production volume and a large screen. As such display devices, an active matrix type liquid crystal display using a thin film transistor (hereinafter abbreviated as TFT) as a switching device is widely spread.

A display device using such a TFT as a conversion element uses an oxide semiconductor material as its constituent material. IGZO (In-Ga-Zn-O-based oxide), which is one of the transparent oxide semiconductor materials, is attracting attention as the oxide-type semiconductor material (see Patent Document 1). Since the IGZO has a high carrier mobility which is second only to the conventionally used polysilicon, and the characteristic variation of the characteristics of the TFT such as amorphous silicon (a-Si) is small, it is promising as a future. The semiconductor materials have begun to be widely used.

However, the display mode of liquid crystal displays such as thin televisions is changing. Specifically, in addition to the flat display (2D), a stereoscopic display (3D) liquid crystal display is provided. The stereoscopic display (3D) type liquid crystal display is realized by switching liquid crystals by adjusting the left and right sides of the display screen to different images. Therefore, for such a stereoscopic display type liquid crystal display, A conversion component that can achieve a higher speed of response is being sought.

In order to respond to changes in the display mode of such a liquid crystal display, development of various oxide-type semiconductor materials such as IGZO is underway. For high response speed TFTs, high carrier mobility is important. For example, the carrier mobility of IGZO is 1 to 2 digits larger than a-Si, and the carrier mobility is about 5 to 10 cm ² /Vs. Therefore, although the IGZO can use a TFT constituent material as a conversion element of a stereoscopic display type liquid crystal display, in order to achieve a high-spectrum liquid crystal display, a TFT constituent material capable of achieving a higher reaction speed is being sought.

In addition, since such an IGZO is referred to as an annealing treatment at 350 ° C or higher in forming a TFT, it is difficult to use it in an organic EL panel or an electronic paper such as a flexible substrate. A display device that cannot be heat treated at a high temperature.

Further, in terms of resource issues and impact on the human body and the environment, it is sought to use an oxide semiconductor material that does not use In or Ga. In this regard, it is also necessary to develop an alternative material for IGZO.

As an alternative material to the IGZO, for example, an oxide-type semiconductor material (ZTO: Zn-Sn-O-based oxide) containing a Zn oxide and a Sn oxide has been disclosed (Patent Document 2, Patent Document 3, and Patent) Document 4). Although the prior art ZTO was developed to achieve high carrier mobility, the heat treatment temperature at the time of TFT formation was not examined, and the applicability to an organic EL panel or electronic paper was not clarified. Therefore, the status quo is still seeking to further improve the ZTO as an alternative to IGZO.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Invention Patent No. 4164562

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-123957

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-37161

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2010-248547

The present invention is based on the above circumstances, and aims to provide an oxide-type semiconductor material (ZTO: Zn-Sn-O-based oxide) containing Zn oxide and Sn oxide as an alternative material for IGZO. It has a high carrier mobility of about 10 cm ² /Vs equal to or higher than IGZO, and does not require a heat treatment at a high temperature of 300 ° C or higher.

In order to solve the problem, the inventors of the present invention have conducted various reviews on dopants contained in an oxide-type semiconductor material containing Zn oxide and Sn oxide, and found that when doping certain specific elements , can produce a ZTO film with high carrier mobility without the need for high temperature heat treatment to drive the TFT

The present invention is characterized in that it contains an oxide type semiconductor material of Zn oxide and Sn oxide, and contains at least one of Mg (magnesium), Ca (calcium), La (yttrium), and Y (yttrium) as a dopant. The atomic ratio of the dopant to the total of the number of atoms of Zn (zinc), Sn (tin), and dopant as the metal element is 0.09 or less.

As long as it is an oxide-type semiconductor material of the present invention, that is, a carrier mobility is equal to or higher than that of IGZO, carrier mobility of about 10 cm ² /Vs can be achieved, and a conversion element such as a TFT can be formed by heat treatment at 250 ° C or lower. In addition, since there is no In and Ga, there is no resource problem and the impact on the human body and the environment is reduced.

The dopant of the oxide-type semiconductor material of the present invention may be any one of Mg, Ca, La, Y, or a combination thereof. Further, the content of the dopant is a total atomic ratio of the metal element Zn, Sn, and the dopant to the dopant of 0.09 or less. Specifically, when the number of atoms of the metal element Zn is x, the number of atoms of Sn is y, and the number of atoms of the dopant is z, it is doped to be z/(x+y+z)≦0.09. Miscellaneous. If the atomic ratio exceeds 0.09, the resistance value of the oxide semiconductor material increases, and semiconductor characteristics cannot be obtained. When the atomic ratio is 0.09 or less, since the carrier density is less than 1 × 10 ¹⁸ cm ^-3 , a carrier density equal to or lower than that of the IGZO film after heat treatment at 350 ° C can be achieved. The lower limit of the dopant content is not limited as long as it can achieve a carrier density equal to or lower than that of IGZO, and a conversion element such as a TFT can be formed by heat treatment at 250 ° C or lower. Under the review by the inventors of the present invention, it has been confirmed that, for example, in the case of Mg, even if the content of the dopant is 0.0015, the oxide semiconductor material of the present invention can be used. Further, in the case of Mg, it is preferred that the content of the dopant is not more than 0.01. When it is less than 0.01, it is easy to achieve good TFT characteristics. Further, it is preferable that when the dopant is Ca, the content of the dopant is less than 0.074, and when the dopant is La, the content of the dopant is less than 0.027, and the doping ratio is less than 0.027. When the dopant is Y, the dopant is contained in an atomic ratio of less than 0.038. Further, it was confirmed that the characteristics of patterning when forming an element were superior to those of the undoped ZTO film using Mg as a dopant.

In the oxide-type semiconductor material of the present invention, in the case where Zn and Sn have a metal element number of A and Sn of Zn, the atomic number of the metal element is B, preferably A/(A+B)=0.4 to 0.8. The ratio is preferably from 0.6 to 0.7. When A/(A+B) is less than 0.4, since the ratio of Sn becomes high, the etching rate of the oxalic acid-based etching liquid is formed when the film formed film is patterned by etching at the time of element formation. It will become extremely slow and not suitable for production steps. In addition, when it exceeds 0.8, since the ratio of Zn becomes high, the resistance to water of the oxide-type semiconductor material becomes low, and in the patterning process of the wiring or the semiconductor layer which is generally used in the formation of the TFT element, The ZTO film is damaged by the influence of the stripping solution of the resist or the washing of the pure water, and the original TFT element characteristics cannot be achieved. In some cases, the ZTO film is dissolved/shedded from the substrate, and the TFT element cannot be formed.

In the present invention, Zr may be further contained as a dopant. Zr (zirconium) can also contribute to the control of the mobility of the carrier of the oxide-type semiconductor material of the present invention. In the present invention, when any one of Mg, Ca, La, Y is used as a dopant, or a combination thereof is used, and Zr is further contained, the content of Zr is preferably such that all the dopants in the material are total. The atomic ratio of the content is 0.09 or less. Further, the content of Zr is preferably a total of the atomic ratio of Zr to 0.005 or less with respect to the total number of atoms of the metal elements Zn (zinc), Sn (tin), and all the dopants constituting the oxide semiconductor material.

The oxide-type semiconductor material of the present invention is very useful for a thin film transistor of a bottom gate type or a top gate type. Such as As described above, as long as the oxide-type semiconductor material of the present invention can achieve high carrier mobility equivalent to or higher than IGZO, low-temperature heat treatment at 250 ° C or lower can be used, so that it is suitable for a stereoscopic display type requiring high reaction speed. The liquid crystal display can also be applied to the formation of a conversion element such as an organic EL panel or an electronic paper using a flexible substrate.

When a conversion element is formed by the oxide semiconductor material of the present invention, it is advantageous to form a thin film formed of the oxide semiconductor material, and it is preferable to form a thin film by sputtering.

Further, when the film of the oxide-type semiconductor material of the present invention is formed by the sputtering method, it is preferable to use a dopant content in relation to the number of atoms of Zn, Sn, and a dopant as a metal element. The total atomic ratio of the dopant is a sputtering target of 0.09 or less. Further, when the number of atoms of the metal element of Zn is A and the number of atoms of the metal element of Sn is B, it is preferable to contain an alloy target of Zn and Sn in a ratio of A/(A+B)=0.4 to 0.8. In this case, a DC power source, a high frequency power source, or a pulsed DC power source (Pulse DC Power) may be used in the sputtering film formation. In particular, when an alloy target is used, since a pulsed DC power source can be used to suppress the formation of a nodule or a surface high-resistance layer which is generated on the surface of the target, and film formation is carried out stably, it is suitable for mass production engineers.

In the oxide-type semiconductor material of the present invention, when Zr is contained as a dopant, it is preferable to use a sputtering target having a predetermined amount of Zr in addition to any one of Mg, Ca, La, and Y. When preparing such a sputtering target, any one of Zn oxide, Sn oxide, Mg, Ca, La, and Y is formed by forming an oxide semiconductor material having a desired composition. The oxide is produced by mixing and sintering with Zr oxide. Further, an oxide of any one or more of Zn oxide and Sn oxide, Mg, Ca, La, and Y may be a dry type ball mill using a grinding ball made of ZrO ₂ as a grinding medium. The mixture is treated to contain Zr. With this dry ball mill, although Zr can be mixed as a dopant, it is preferable to consider the uniformity of the oxide semiconductor material, and it is preferable to mix Zr oxide.

When the device is formed by using the oxide-type semiconductor material of the present invention, the film formation by the above-described sputtering method can be applied, but a film formation method other than sputtering such as pulsed laser deposition can be applied. Further, an element using the oxide-type semiconductor material of the present invention may be formed by a method of dispersing a dispersing agent of a nanoparticle of a semiconductor material in a solvent or by forming a circuit by an inkjet method.

According to the oxide-type semiconductor material of the present invention, carrier mobility equivalent to or higher than that of IGZO can be achieved, and a conversion element such as a TFT can be formed by low-temperature heat treatment at 250 ° C or lower. In addition, since it does not contain In and Ga, there is no problem in terms of resources, and the impact on the human body and the environment can be reduced.

(Example)

Hereinafter, embodiments of the present invention will be described.

First Embodiment: This first embodiment describes a case where Mg is used as a dopant.

First, the oxide semiconductor material of the first embodiment will be described. The production of a sputtering target.

Preparation of target: Weigh a specified amount of ZnO powder calcined at 500 ° C in the atmosphere, SnO ₂ powder calcined at 1050 ° C in the atmosphere, and MgO powder without calcination. The mixture was placed in a resin pot (capacity 4 L) and mixed in a ball mill. The ball mill was mixed at a number of revolutions of 130 rpm and a mixing time of 12 hours. Thereafter, the mixed powder was sieved with a sieve having a mesh size of 500 μm and a wire diameter of 315 μm. The mixed powder of the sieve having the removed coarse particles was filled in a ψ100 mm carbon press, and a sintered body was produced by hot pressing. The hot pressing conditions were carried out under a pressure of 3 L/min of Ar gas and a pressure of 9.4 MPa, and the temperature was raised to 1050 ° C, and then held under a pressure of 25 MPa for 90 minutes to be naturally cooled, and then the sintered body was taken out. In the order disclosed above, a sintered body target for forming a film having the atomic ratio of each atom shown in Table 1 was formed.

Next, a film formation method by sputtering using the produced sintered body target, and evaluation of the film will be described. Film formation was carried out using a commercially available single wafer sputtering apparatus (manufactured by Tokki Co., Ltd.: SML-464). The sputtering condition is that the ultimate vacuum is 1×10 ^-5 Pa, and the Ar/O ₂ mixed gas is used as the sputtering gas, and the sputtering gas pressure is set to 0.4 Pa, and the oxygen partial pressure is 0.01 Pa at room temperature (25 ° C). A glass substrate (manufactured by Nippon Electric Glass Co., Ltd.: OA-10) was formed into a film having a thickness of about 100 nm by DC sputtering at 150 W.

The composition of the film to be formed was analyzed by using an ICP (Inductively Coupled Plasma) luminescence spectroscopic analyzer (manufactured by SII Nanotechnology Co., Ltd.: Vista Pro). In Table 1, Zn/(Zn+Sn) is calculated from the measured values of Zn, Sn, and Mg. The atomic ratio of Mg/(Zn+Sn+Mg) is described. Further, when used for a thin film transistor (TFT) or the like, the composition of the oxide type semiconductor material can be identified by cutting the element and observing the cross section of the element by using a transmission electron micromirror (TEM) or the like. An oxide-type semiconductor material layer can be determined by analyzing the portion by EDX.

Next, each sample which has been formed into a film was annealed at 200 ° C and 300 ° C for 1 hour in an atmospheric environment, and Hall effect was measured, and the specific resistance value and carrier movement of each sample were determined. Sex, carrier density. The measurement of the Hall effect was carried out by using a commercially available Hall effect measuring apparatus (manufactured by Nanometrics Japan Co., Ltd.: HL5500PC) using each sample cut into 10 mm × 10 mm square. The results of the specific resistance value, carrier mobility, and carrier density of each sample are shown in Table 1.

TFT evaluation: Using the above film as a channel layer, a thin film transistor (TFT) was fabricated using a metal mask. Fig. 1 is a schematic cross-sectional view showing a TFT element formed (Fig. 1(A)) and a plan view of a plane (Fig. 1(B)). As shown in Fig. 1(A), the formation of the TFT is first performed by forming an Al alloy (thickness 2000 Å) as the gate electrode 20 on the glass substrate 10. Here, DC sputtering is performed at a sputtering pressure of 0.4 Pa and an input power of 1000 W. Next, a film of a SiNx film (thickness: 3000 Å) as the gate insulating film 30 is formed. Here, the film formation was carried out by a plasma chemical vapor deposition (plasma CVD) apparatus (manufactured by Samco Co., Ltd.: PD-2202L), and at a substrate temperature of 350 ° C and an input power of 250 W under plasma CVD. get on. The flow rate of the material gas was SiH ₄ : NH ₃ : N ₂ = 100 cc: 10 cc: 200 cc. Next, the above-described ZTO-MgO film (thickness: 300 Å) was formed as the channel layer 40. Here, DC sputtering was performed at a sputtering pressure of 0.4 Pa and an input power of 150 W. The channel has a W/L of 22. Finally, a film of ITO was used as a film of the source electrode 50 (thickness 2000 Å) and the drain electrode 51 (thickness 2000 Å). Here, DC sputtering was performed at a sputtering pressure of 0.4 Pa and an input power of 600 W. The element size of the TFT fabricated in this manner is as shown in Fig. 1(B). The numerical unit of each length of the first (B) diagram is millimeter (mm).

The transfer characteristic of the produced TFT was measured by a semiconductor analyzer (Semiconductor Device Analyzer B1500A, manufactured by Agilent Technologies, Inc.). The gate voltage (Vds) applied during the measurement is 1 to 5 V, and the gate voltage (Vgs) is measured in the range of -10 to 20V. The measurement results of the TFT transfer characteristics are shown in Figs. 2 and 3. Fig. 2 is a view showing TFT characteristics in the case of Zn/(Zn+Sn) = 0.66, Mg/(Zn + Sn + Mg) = 0.015 (Example 5, heat treatment temperature: 200 ° C), and Fig. 3 is a view showing Zn. / (Zn + Sn) = 0.62, TFT characteristics in the case where no Mg dopant was added (Comparative Example 4, heat treatment temperature: 200 ° C). In addition, in FIGS. 2 and 3, the left side of the vertical axis is the logarithmic current of the Ids (A) value, and the right side of the vertical axis is the √Id value axis represented by the decimal point.

As shown in Table 1, it is found that if the atomic ratio of Mg content is 0.0015 to 0.079, the carrier density of the sputtered film after heat treatment at 200 ° C falls below 1 × 10 ¹⁵ cm ^-3 and does not reach 1 × 10 ¹⁸ cm ^{-3 .} The scope. Further, as shown in Fig. 2, it was found that when Zn/(Zn+Sn) = 0.66 and the Mg content is atomic ratio of 0.015 (Mg / (Zn + Sn + Mg): Example 6) (carrier density 4.75 × 10 ¹⁶ cm ^-3 ), the TFT characteristic has an on/off ratio of 5 digits, and exhibits good TFT characteristics. As a result of measuring the characteristics of the TFT by seven elements, the threshold voltage Vth(V) was 5.88±1.94V, the field effect mobility μ(cm ² /Vs) was 5.84±0.5 cm ² /Vs, and the S value (V/dec). It is 1.07±0.5V/dec. On the other hand, as shown in Fig. 3, it was confirmed that Zn/(Zn+Sn) = 0.62, and in the case where no Mg dopant was added (carrier density: 3.62 × 10 ¹⁸ cm ^-3 ), the TFT characteristics were The on/off ratio is 2 digits, and the ZTO film system of this composition cannot function as a channel layer. In addition, the TFT characteristics were measured for seven elements without adding a Mg dopant. As a result, five of the elements were unoff components that could not be on/off, and the remaining two components had a threshold voltage Vth(V) of -12.9 ± 2.33 V, field effect mobility μ (cm ² /Vs) was 13.7 ± 3.54 cm ² /Vs, and S value (V / dec) was 9.07 ± 2.45 V / dec. Further, the field effect mobility μ is a value obtained by measuring the characteristics of the TFT by forming a TFT element, and the carrier mobility of Table 1 is obtained by measuring the Hall effect of the film formed. Further, the S value represents a subthreshold swing value of the transistor characteristics.

Further, as shown in Fig. 4, it was confirmed that Zn/(Zn + Sn) = 0.66. The Mg content is atomic ratio of 0.009 (Mg/(Zn+Sn+Mg): in the case of Example 5), (carrier density: 5.90 × 10 ¹⁶ cm ^-3 ), and the TFT characteristic on/off ratio is 5 digits. , showing good TFT characteristics. As a result of measuring the characteristics of the TFT by seven elements, the threshold voltage Vth(V) was 0.43±0.42V, the field effect mobility μ(cm ² /Vs) was 6.02±0.63 cm ² /Vs, and the S value (V/dec). It is 0.73 ± 0.3V / dec. Further, the same TFT characteristic investigation was carried out in Example 8, and the result of measuring one element among the seven elements produced was measured. The threshold voltage Vth (V) was 5.75 V, and the field effect mobility μ (cm ^{2 )} /Vs) is 0.70 cm ² /Vs, and the S value (V/dec) is 0.85 V/dec. Based on the results of this TFT characteristic, Comparative Example 5, Example 6, and Example 8 were found to have a very good TFT system of Example 5 (Mg content atomic ratio of 0.009 (Mg/(Zn+Sn+Mg)). TFT characteristics.

Second Embodiment: This second embodiment describes a case where Ca, La, and Y are used as dopants.

The target using these dopants was produced in the same manner as in the first embodiment, and was formed into a film having the composition shown in Table 2. Calculate the atomic ratio of Zn/(Zn+Sn) and dopant/(Zn+Sn+ dopant) from the measured values of Zn, Sn, and dopant (Ca, La, Y) in Table 2. And record it. Further, the film formation conditions, the specific resistance value, the carrier mobility, and the carrier density were measured in the same manner as in the first embodiment. The results are shown in Table 2.

As shown in Table 2, it is known that a ZTO film using Ca, La, and Y as a dopant has no practical problem in specific resistance even when heat-treated at 200 ° C, and the carrier density falls below 10 ¹⁵ cm ^-3 . Not in the range of 10 ¹⁸ cm ^-3 . Further, according to the TFT characteristics of this composition, a good result of an on/off ratio of 5 digits was also obtained.

Further, as shown in Fig. 5, it is found that in the case where Zn/(Zn+Sn) = 0.66 and the Ca content is 0.003 (Ca/(Zn + Sn + Ca): Example 12) (carrier density) 5.10 × 10 ¹⁶ cm ^-3 ), the TFT characteristics are on/off ratio of 5 digits, and exhibit good TFT characteristics. As a result of measuring the TFT characteristics of four of the seven elements, the threshold voltage Vth (V) was 1.99 ± 0.83 V, and the field effect mobility μ (cm ² /Vs) was 5.20 ± 0.72 cm ² /Vs, S value. (V/dec) is 0.55 ± 0.08 V / dec.

Third Embodiment: This third embodiment describes a case where Mg and Zr are used as dopants.

The target of using Mg and Zr as a dopant is a method of weighing a specified amount of ZnO powder calcined at 500 ° C in an atmospheric environment at a temperature of 1050 ° C in the same manner as in the first embodiment. The calcined SnO ₂ powder, the un-fired MgO powder and the ZrO ₂ powder were mixed in a ball mill (mixing conditions were the same as in the first embodiment). Next, a sintered body is produced by sieving treatment and hot pressing (the sieving treatment and the hot pressing conditions are the same as in the first embodiment). Next, this sintered body was used as a sputtering target, and film formation was performed according to the composition shown in Table 3. Calculate the atomic ratio of Zn/(Zn+Sn) and (Mg+Zr)/(Zn+Sn+Zr+Mg) from the measured values of Zn, Sn, and dopant (Mg, Zr) in Table 3. And record it. Further, the film formation conditions, the specific resistance value, the carrier mobility, and the carrier density were measured in the same manner as in the first embodiment. The results are shown in Table 3.

As shown in Table 3, it was found that Mg and Zr were used as dopants (wherein the atomic ratio of Mg dopant (Mg/(Zn+Sn+Zr+Mg)) was 0.0000849, and the atomic ratio of the Zr dopant ( Zr/(Zn+Sn+Zr+Mg)) is 0.0012, so the ZTO film with a total atomic ratio of 0.0012849), even if heat treated at 200 °C, the specific resistance value is practically no problem, and the carrier density falls into 10 ¹⁵ cm ^-3 or more, less than 10 ¹⁸ cm ^-3 range. Further, according to the TFT characteristics of such a composition, a good result in which the on/off ratio is 5 bits or more is obtained.

Further, in the target production, the change in the Zr content of the oxide-type semiconductor material was investigated by performing a mixing treatment using a dry ball mill using a ZrO ₂ grinding ball. Specifically, in the same manner as in the above-described Example 17, a specified amount of ZnO powder, SnO ₂ powder, and MgO powder were mixed and treated in a dry ball mill using a ZrO ₂ grinding ball to form a sintered body (mixing conditions, The screening treatment and hot pressing conditions are the same). As a result, it was found that the film-forming oxide semiconductor material had a Zr content of 0.000046 after the mixing treatment for 12 hours, and 0.000063 when it was 20 hours. Further, it was confirmed that the oxide-type semiconductor material containing Zr by the ZrO ₂ grinding ball has the same electronic characteristics as in the seventeenth embodiment.

(industrial availability)

The oxide-type semiconductor material of the present invention is extremely useful for a higher reaction speed as a conversion element such as a stereoscopic display type liquid crystal display. The TFT constitutes a material. Further, since the oxide-type semiconductor material of the present invention can be used by low-temperature heat treatment, it is suitable for utilizing an organic EL panel and an electronic paper such as a flexible substrate, and has a viewpoint on resources or influence on the human body and the environment. In view of the industry, the value of utilization in the industry is also high.

10‧‧‧ glass substrate

20‧‧‧gate electrode

30‧‧‧gate insulating film

40‧‧‧Channel layer

50‧‧‧Source electrode

51‧‧‧汲electrode

Figure 1 is a schematic diagram of a TFT element

Fig. 2 Measurement chart of TFT characteristics (Example 6, 200 ° C)

Fig. 3 Measurement chart of TFT characteristics (Comparative Example 4, 200 ° C)

Fig. 4 Measurement chart of TFT characteristics (Example 5, 200 ° C)

Figure 5 is a measurement chart of TFT characteristics (Example 12, 200 ° C)

10‧‧‧ glass substrate

20‧‧‧gate electrode

30‧‧‧gate insulating film

40‧‧‧Channel layer

50‧‧‧Source electrode

51‧‧‧汲electrode

Claims (5)

An oxide-type semiconductor material comprising a Zn oxide and a Sn oxide. When the number of metal elements having a metal atomic number of A and Sn of Zn is B, A/(A+B)= The ratio of 0.4 to 0.8 contains Zn and Sn, and contains at least one of Mg, Ca, La, and Y as a dopant. The atomic number of the metal element Zn is x, and the number of atoms of Sn is y, doping. In the case where the atomic number of the metal element of the agent is z, z / (x + y + z) ≦ 0.09. The oxide-type semiconductor material according to claim 1, wherein Zr is further contained as a dopant. A thin film transistor using a bottom gate type or a top gate type thin film transistor formed of the oxide type semiconductor material according to claim 1 or 2. A sputtering target comprising a Zn oxide and a Sn oxide. When the number of metal elements having a metal atomic number of A and Sn is B, the ratio of A/(A+B)=0.4 is The ratio of up to 0.8 contains Zn and Sn, and further contains at least one of Mg, Ca, La, and Y as a dopant; the content of the dopant is such that the atomic number of the metal element Zn is x, the atom of Sn In the case where the number is y and the number of atoms of the metal element of the dopant is z, z / (x + y + z) ≦ 0.09. The sputtering target according to claim 4, wherein Zr is further contained as a dopant.