WO2010024034A1 - Sputtering target and oxide semiconductor thin film formed therefrom - Google Patents

Sputtering target and oxide semiconductor thin film formed therefrom Download PDF

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WO2010024034A1
WO2010024034A1 PCT/JP2009/061629 JP2009061629W WO2010024034A1 WO 2010024034 A1 WO2010024034 A1 WO 2010024034A1 JP 2009061629 W JP2009061629 W JP 2009061629W WO 2010024034 A1 WO2010024034 A1 WO 2010024034A1
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thin film
oxide semiconductor
semiconductor thin
sputtering
oxide
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PCT/JP2009/061629
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French (fr)
Japanese (ja)
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一吉 井上
太 宇都野
恒太 寺井
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出光興産株式会社
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Priority to JP2010526615A priority Critical patent/JP5438011B2/en
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    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/08—Oxides
    • C23C14/086—Oxides of zinc, germanium, cadmium, indium, tin, thallium or bismuth
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    • C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
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    • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
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Definitions

  • the present invention relates to a sintered body, a sputtering target, an oxide semiconductor thin film, and a thin film transistor.
  • Oxide semiconductor films made of several metal complex oxides have high mobility and visible light transmission, so that liquid crystal display devices, thin film electroluminescence display devices, electrophoretic display devices, powder transfer display devices A wide variety of applications such as switching elements and drive circuit elements are being studied.
  • the oxide semiconductor film made of indium oxide-gallium oxide-zinc oxide is most popular.
  • indium oxide-zinc oxide, tin oxide added with zinc oxide (ZTO), indium oxide-zinc oxide-tin oxide added with gallium oxide, and the like are known. Since these are different in ease of manufacture, price, characteristics, etc., they are used as appropriate according to their applications.
  • an oxide of In, Ga, and Zn (IGZO), or an oxide semiconductor film containing the oxide of In, Ga, and Zn as a main component has an advantage of higher mobility than an amorphous silicon film, and thus attracts attention.
  • a sputtering target used for forming an oxide semiconductor film composed of indium oxide-gallium oxide-zinc oxide is manufactured through steps of mixing raw material powder, calcining, pulverizing, granulating, molding, sintering and reducing. .
  • a multi-step process up to the reduction of the bulk resistance due to the reduction of the sputtering target has the disadvantage that the productivity is lowered and the cost is increased.
  • the conductivity after the reduction was at most about 90 S / cm (bulk specific resistance: 11 m ⁇ cm), and a sufficiently low resistance target could not be obtained.
  • the sputtering target composed of indium oxide-gallium oxide-zinc oxide has a high bulk resistance, and the compound represented by InGaO 3 (ZnO) m grows abnormally during DC sputtering, resulting in abnormal discharge or a film obtained. May be unstable or become a conductive film.
  • Patent Document 1 discloses a sputtering target in which an indium oxide-zinc oxide based oxide further contains a lanthanoid element. However, it has been difficult to form an oxide semiconductor having low carrier concentration and semiconductor characteristics using this sputtering target.
  • Patent Document 2 discloses an oxide semiconductor film containing indium oxide and a lanthanoid element.
  • Patent Document 3 discloses a substrate for an organic EL element containing indium oxide, zinc oxide, and a lanthanoid metal oxide. The blending amount of the lanthanoid metal oxide is 0.1 to less than 20 atomic% with respect to all metal atoms.
  • Patent document 4 discloses a sputtering target containing zinc oxide, indium oxide and a color unevenness preventing agent which is a compound having a lanthanum oxide type crystal structure belonging to the hexagonal system.
  • An object of this invention is to provide the low-resistance sputtering target without an abnormal discharge during sputtering.
  • An object of the present invention is to provide an oxide semiconductor thin film having a low carrier concentration and stable semiconductor characteristics.
  • the following sintered body, sputtering target, oxide semiconductor thin film and the like are provided.
  • the atomic ratio is 0.2 ⁇ In / (In + Zn) ⁇ 0.97, 0.03 ⁇ Zn / (In + Zn) ⁇ 0.8, and 0.2 ⁇ (Ln / (In + Zn + Ln) ⁇ Sintered body which is 0.5. 2.
  • the atomic ratio is 0.2 ⁇ In / (In + Zn) ⁇ 0.97, 0.03 ⁇ Zn / (In + Zn) ⁇
  • the oxide semiconductor thin film which is 0.8 and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.5. 6). 6.
  • an oxide semiconductor thin film having a low carrier concentration and stable semiconductor characteristics can be provided.
  • FIG. 6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 2.
  • 6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 3.
  • 6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 4.
  • 6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 5.
  • 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 6.
  • 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 7.
  • 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 8.
  • 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 9.
  • 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 10.
  • FIG. 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 11.
  • FIG. 10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 12.
  • 6 is a chart showing an X-ray diffraction pattern of a target obtained in Comparative Example 1.
  • the sintered body of the present invention includes a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), and InLnO 3 (Ln excludes Pr and Pm). A compound represented by a trivalent lanthanoid element).
  • This sintered body can be suitably used as a sputtering target.
  • the sintered body of the present invention may further contain In 2 O 3 .
  • the sintered body of the present invention contains zinc oxide as a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20). This is because a hexagonal layered compound represented by In 2 O 3 (ZnO) m (where m is an integer of 2 to 20) and InGaO 3 (ZnO) m (where m is an integer of 1 to 20). This is because the bulk resistance generally increases when an insulating oxide such as Ga is contained when comparing the bulk resistance of the hexagonal layered compounds represented by the formula (1).
  • the hexagonal layered compound is L. Dupont et al., Journal of Solid State Chemistry 158, 119-133 (2001), Toshihiro Moriga et al., J. Am. Ceram. Soc., 81 (5) 1310. -16 (1998).
  • the m of In 2 O 3 (ZnO) m that is a hexagonal layered compound contained in the sintered body of the present invention is preferably 3 to 7.
  • the sintered body of the present invention contains an oxide of a lanthanoid element as a compound represented by InLnO 3 (wherein Ln is a trivalent lanthanoid element excluding Pr and Pm).
  • Ln is a trivalent lanthanoid element excluding Pr and Pm.
  • the sintered body contains an oxide of a lanthanoid element as InLnO 3 , there is no insulating Ln 2 O 3 , and as a result, abnormal discharge can be reduced and stable film formation becomes possible.
  • lanthanoid elements have a strong binding force with oxygen and do not generate oxygen vacancies, a thin film having a specific resistance suitable for semiconductor applications can be obtained during film formation.
  • Ln 2 O 3 is doped into indium oxide (In 2 O 3 ), and there is no insulating Ln 2 O 3 , resulting Stable sputtering becomes possible.
  • the crystal particles in the sintered body are refined to a size of, for example, a particle size of 5 ⁇ m, preferably less than 3 ⁇ m.
  • Ln is a trivalent lanthanoid element excluding Pr and Pm, that is, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
  • a thin film obtained from a sintered body containing Pr and Pm may have radioactivity.
  • InLnO 3, InLaO 3, InNdO 3 , InSmO 3, InEuO 3, InGdO 3, InTbO 3, InDyO 3, InHoO 3, InErO 3, InTmO 3, InYbO 3, InLuO 3 and the like to handle Since it is easy, InSmO 3 , InGdO 3 , InDyO 3 , InErO 3 , InYbO 3 or the like is preferably used.
  • the atomic ratio of indium, zinc and lanthanoid elements is 0.2 ⁇ In / (In + Zn) ⁇ 0.97 0.03 ⁇ Zn / (In + Zn) ⁇ 0.8, and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.5, Preferably 0.25 ⁇ In / (In + Zn) ⁇ 0.95, 0.05 ⁇ Zn / (In + Zn) ⁇ 0.75, and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.45, More preferably, 0.25 ⁇ In / (In + Zn) ⁇ 0.9, 0.1 ⁇ Zn / (In + Zn) ⁇ 0.75, and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.4.
  • the atomic ratio can be obtained by ICP emission analysis.
  • the resulting thin film may become conductive or the durability of the thin film may be poor. Further, when the atomic ratio In / (In + Zn) is 0.97 or more, the obtained thin film may become conductive or the thin film may be crystallized.
  • the resulting thin film may become conductive or the thin film may crystallize. Moreover, when Zn / (In + Zn) is 0.8 or more, the obtained thin film may become conductive, or the durability of the thin film may be poor.
  • the resulting thin film may become conductive. Further, when the atomic ratio Ln / (In + Zn + Ln) is 0.5 or more, the obtained thin film has almost no carriers and becomes an insulating film, which may not function as a semiconductor.
  • the sintered body of the present invention preferably has an In content [In / (total metal cation): atomic ratio] to the total cation metal element, and an Ln content [Ln / (total metal cation) to the total metal cation element]. : Atomic ratio]. That is, the sintered body preferably satisfies the following formula. In / (all metal cations)> Ln / (all metal cations)
  • the lanthanoid oxide (Ln 2 O 3 ) in the sintered body becomes InLnO 3 and the conductivity of the sintered body can be improved. Thereby, the bulk resistance of a sintered compact can be reduced and stable sputtering becomes possible.
  • Ln 2 O 3 in the sintered body does not become InLnO 3 but exists in the form of insulating Ln 2 O 3 , which may cause abnormal discharge during sputtering. is there.
  • the sintered body of the present invention preferably has a bulk resistance of less than 5 m ⁇ cm, more preferably 3 m ⁇ cm or less, and even more preferably 1 m ⁇ cm or less.
  • a bulk resistance of the sintered body is 5 m ⁇ cm or more, abnormal discharge or foreign matter (nodules) may occur during sputtering.
  • a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), a compound represented by InLnO 3 , and in some cases, InLnO 3 (ZnO) m You may contain as a hexagonal layered compound represented.
  • the highly insulating Ln 2 O 3 causes abnormal discharge, which causes foreign matter in the deposited film. May occur, or the surface accuracy of the thin film may be reduced.
  • the sintered body of the present invention is a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), InLnO 3 (Ln excludes Pr and Pm 3 A valent lanthanoid element), and optionally In 2 O 3 , or only these compounds.
  • “Substantially” means that the sintered body of the present invention is a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), InLnO 3 ( Ln consists of a compound represented by a trivalent lanthanoid element excluding Pr and Pm), and optionally In 2 O 3 , and may further contain the following components.
  • the sintered body of the present invention may contain a positive tetravalent metal oxide as a trace impurity.
  • the positive tetravalent metal oxide does not generate carriers due to doping in indium oxide, and can facilitate carrier control of the oxide semiconductor thin film.
  • the positive tetravalent metal oxide is preferably CeO 2 , GeO 2 , ZrO 2 , SnO 2 , TiO 2 or the like, and more preferably CeO 2 , GeO from the viewpoint of the stability of the obtained oxide semiconductor thin film. 2 and ZrO 2 .
  • the content of the positive tetravalent metal oxide is, for example, 50 to 3000 ppm, preferably 100 to 2000 ppm, more preferably 200 to 1000 ppm. If the content of the positive tetravalent metal oxide is less than 50 ppm, the effect obtained by addition may be small. On the other hand, if the content of the positive tetravalent metal oxide exceeds 3000 ppm, it becomes difficult to control the carrier of the obtained thin film, the thin film becomes conductive, and the off-current value, which is a semiconductor characteristic, increases. The thin film may not be stable.
  • indium oxide (In 2 O 3 ), zinc oxide (ZnO) and lanthanoid oxide (Ln 2 O 3 ) powders are mixed, and the mixture is pulverized and sintered.
  • the specific surface area of the indium oxide powder is preferably 8 to 10 m 2 / g
  • the specific surface area of the zinc oxide powder is 2 to 4 m 2 / g
  • the specific surface area of the lanthanide oxide is preferably 5 to 15 m 2 / g.
  • the median diameter of the indium oxide powder is preferably 1 to 2 ⁇ m
  • the median diameter of the zinc oxide powder is 0.8 to 1.6 ⁇ m
  • the median diameter of the lanthanide oxide is preferably 1 to 2 ⁇ m.
  • the mixing ratio of indium oxide powder, zinc oxide powder, and lanthanoid oxide powder is prepared so that the atomic ratio of each element becomes the above-mentioned preferable atomic ratio. That's fine.
  • the mixed powder containing indium oxide powder, zinc oxide powder, and lanthanoid oxide powder is used, other components that improve the characteristics of the sintered body may be added.
  • the mixed powder is mixed and ground using, for example, a wet medium stirring mill. At this time, pulverization is performed so that the specific surface area after pulverization is 1.5 to 2.5 m 2 / g higher than the specific surface area of the raw material mixed powder, or the average median diameter after pulverization is 0.6 to 1 ⁇ m. It is preferable to do.
  • the raw material powder thus adjusted, it is possible to obtain an oxide sintered body having a high density (for example, a relative density of 95% or more) without requiring any calcination process, and no reduction process is required. Can be.
  • the increase in the specific surface area of the raw material mixed powder is less than 1.5 m 2 / g or the average median diameter of the raw material mixed powder after pulverization exceeds 1 ⁇ m, the sintered density may not be sufficiently increased.
  • the increase in the specific surface area of the raw material mixed powder exceeds 2.5 m 2 / g, or if the average median diameter after pulverization is less than 0.6 ⁇ m, contamination from the pulverizer during pulverization (impurity contamination amount) ) May increase.
  • each powder can be measured by the BET method.
  • the median diameter of the particle size distribution of each powder can be measured with a particle size distribution meter. These values can be adjusted by pulverizing the powder by a dry pulverization method, a wet pulverization method or the like.
  • the raw material after the pulverization process is dried with a spray dryer or the like and then molded.
  • a known method such as pressure forming or cold isostatic pressing can be employed.
  • the obtained molded body is sintered to obtain a sintered body.
  • Sintering is preferably performed at 1350 to 1450 ° C. for 2 to 20 hours. When the temperature is lower than 1350 ° C., the density is not improved. When the temperature exceeds 1450 ° C., zinc is evaporated, the composition of the sintered body is changed, or voids (voids) are generated in the sintered body due to the evaporation. There is.
  • Sintering is preferably performed in an oxygen atmosphere by circulating oxygen or under pressure. Thereby, transpiration of zinc can be suppressed, and a sintered body free from voids (voids) can be obtained.
  • the obtained sintered body can be used as a sputtering target by performing processing such as polishing.
  • the sintered body is ground by, for example, a surface grinder so that the surface roughness Ra is 5 ⁇ m or less.
  • the sputter surface of the target may be mirror-finished so that the average surface roughness Ra is 1000 angstroms or less.
  • a known polishing technique such as mechanical polishing, chemical polishing, mechanochemical polishing (a combination of mechanical polishing and chemical polishing) can be used.
  • polishing to # 2000 or more with a fixed abrasive polisher polishing liquid: water
  • lapping with loose abrasive lapping abrasive: SiC paste, etc.
  • lapping by changing the abrasive to diamond paste can be obtained by:
  • Such a polishing method is not particularly limited.
  • the obtained sputtering target By bonding the obtained sputtering target to a backing plate, it can be used by being mounted on various devices.
  • the physical film forming method include a sputtering method, a PLD (pulse laser deposition) method, a vacuum deposition method, and an ion plating method.
  • cleaning, etc. can be used for the cleaning process of a sputtering target.
  • cleaning, etc. can be used for the cleaning process of a sputtering target.
  • cleaning, etc. can be used for the cleaning process of a sputtering target.
  • ultrasonic cleaning and the like can also be performed.
  • a method of performing multiple oscillation at a frequency of 25 to 300 KHz is effective.
  • it is preferable to perform ultrasonic cleaning by multiplying twelve types of frequencies in 25 KHz increments between frequencies of 25 to 300 KHz.
  • the oxide semiconductor thin film of the present invention contains In, Zn, and Ln (Ln is a trivalent lanthanoid element excluding Pr and Pm), and the atomic ratio thereof is 0.2 ⁇ In / (In + Zn) ⁇ 0.97 0.03 ⁇ Zn / (In + Zn) ⁇ 0.8, and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.5, Preferably 0.25 ⁇ In / (In + Zn) ⁇ 0.95, 0.05 ⁇ Zn / (In + Zn) ⁇ 0.75, and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.45, More preferably, 0.25 ⁇ In / (In + Zn) ⁇ 0.9, 0.1 ⁇ Zn / (In + Zn) ⁇ 0.75, and 0.2 ⁇ Ln / (In + Zn + Ln) ⁇ 0.4.
  • the oxide semiconductor thin film of the present invention has a low carrier concentration and stable semiconductor characteristics.
  • the thin film may become conductive or the durability of the thin film may be poor. Further, when the atomic ratio In / (In + Zn) is 0.97 or more, the thin film may become conductive or the thin film may be crystallized.
  • the thin film When the atomic ratio Zn / (In + Zn) is 0.03 or less, the thin film may become conductive or the thin film may crystallize. Moreover, when Zn / (In + Zn) is 0.8 or more, the thin film may become conductive or the durability of the thin film may be poor.
  • the thin film may become conductive.
  • the atomic ratio Ln / (In + Zn + Ln) is 0.5 or more, the thin film has almost no carriers and becomes an insulating film, which may not function as a semiconductor.
  • the carrier density of the oxide semiconductor thin film of the present invention is preferably less than 10 18 / cm 3 , more preferably 10 15 / cm 3 or more and less than 10 18 / cm 3 , and even more preferably 10 15 / cm 3. This is less than 5 ⁇ 10 17 / cm 3 .
  • the lower limit of the carrier density of the oxide semiconductor thin film is not particularly limited, but is, for example, 10 12 / cm 3 or more.
  • the carrier concentration of the oxide semiconductor thin film can be achieved by setting the composition ratio of the present invention.
  • the oxide semiconductor thin film can sufficiently function as a semiconductor.
  • the carrier density can be adjusted, for example, by an oxygen partial pressure at the time of forming an oxide semiconductor thin film described later.
  • the semiconductor characteristics of the oxide semiconductor thin film of the present invention are preferably On / Off value> 10 6 , field-effect mobility> 2 cm 2 / V ⁇ sec, threshold voltage (Vth) ⁇ 10 V, and S value ⁇ 5. If these conditions are satisfied, the oxide semiconductor thin film can sufficiently function as a driving thin film transistor for liquid crystal display, a driving thin film transistor for organic EL, or the like.
  • the oxide semiconductor thin film of the present invention can be formed by sputtering the sputtering target of the present invention at a sputtering pressure of 0.1 to 2 Pa and an oxygen partial pressure of 2 to 20% of the sputtering pressure.
  • the sputtering pressure is 0.1 to 2 Pa, preferably 0.2 to 1 Pa.
  • the sputtering pressure is less than 0.1 Pa, the film formation is performed at a high vacuum, and the sputtering rate may decrease, or the cost may increase due to the high vacuum.
  • the sputtering pressure exceeds 2 Pa, the sputtering plasma may not be stable, and the sputtering rate may decrease, or the film quality of the resulting thin film may decrease.
  • the oxygen partial pressure is 2 to 20%, preferably 3 to 10%, more preferably 4 to 8% of the sputtering pressure. Since oxygen controls oxygen vacancies in the resulting thin film, it is necessary to strictly control the oxygen partial pressure during sputtering as described above. When the oxygen partial pressure is less than 2% of the sputtering pressure, the resulting thin film may become a conductive thin film, or the off-current that is a semiconductor characteristic may increase. Further, when the oxygen partial pressure exceeds 20% of the sputtering pressure, the thin film takes in a large amount of oxygen, and there is a possibility that the field effect mobility, which is a semiconductor characteristic, is lowered.
  • the oxygen partial pressure is not particularly limited as long as it is 2 to 20% of the sputtering pressure, but the optimum oxygen partial pressure varies depending on the content of the lanthanoid element in the sputtering target.
  • Lanthanoid elements trivalent lanthanoid elements excluding Pr and Pm usually have an effect of facilitating incorporation of oxygen into the thin film during film formation and reducing the amount of oxygen vacancies in the thin film. Therefore, when the target lanthanoid element content is low, the oxygen partial pressure during sputtering is increased, and when the lanthanoid element content is high, the oxygen partial pressure during sputtering is preferably decreased.
  • the sputtering is preferably performed in an atmosphere where the partial pressure of water and the partial pressure of oxygen satisfy 10 ⁇ (oxygen partial pressure / water partial pressure) ⁇ 200.
  • the above formula is more preferably 15 ⁇ (oxygen partial pressure / water partial pressure) ⁇ 150, and more preferably 20 ⁇ (oxygen partial pressure / water partial pressure) ⁇ 100.
  • the oxygen partial pressure / water partial pressure When the oxygen partial pressure / water partial pressure is 10 or less, durability of the resulting oxide semiconductor thin film may be reduced, off-current may be increased, or field-effect mobility may be reduced. On the other hand, when the oxygen partial pressure / water partial pressure is 200 or more, the cost of exhausting water molecules is high, and thus productivity may be reduced.
  • FIG. 1 is a schematic cross-sectional view showing an embodiment of the thin film transistor of the present invention.
  • the thin film transistor 1 is a channel etch type thin film transistor.
  • the gate electrode 20 is sandwiched between the substrate 10 and the insulating film 30, and the oxide semiconductor thin film 40 of the present invention is stacked on the gate insulating film 30 as an active layer.
  • a source electrode 50 and a drain electrode 52 are provided so as to cover the vicinity of the end of the oxide semiconductor thin film 40.
  • a channel portion 60 is formed in a portion surrounded by the oxide semiconductor thin film 40, the source electrode 50 and the drain electrode 52.
  • FIG. 2 is a schematic cross-sectional view showing another embodiment of the thin film transistor of the present invention.
  • the thin film transistor 2 is an etch stopper type thin film transistor.
  • the thin film transistor 2 has the same configuration as the thin film transistor 1 described above except that an etch stopper 70 is formed so as to cover the channel portion 60.
  • a source electrode 50 and a drain electrode 52 are provided so as to cover the vicinity of the end of the oxide semiconductor thin film 40 and the vicinity of the end of the etch stopper 70.
  • the thin film transistor of the present invention is not limited to a channel etch type or etch stopper type transistor, and an element configuration known in this technical field can be adopted.
  • Example 1 Manufacture of sputtering target
  • the obtained mixed powder was dried with a spray dryer, filled in a mold, and press-molded.
  • the obtained molded body was sintered in an oxygen atmosphere at 1420 ° C. for 20 hours to obtain a sintered body, and further cut to obtain a sputtering target. It was confirmed that the relative density of the target obtained (the value obtained by dividing the density of the mixed oxide by weight and divided by the actually measured density) was 95% or more.
  • the measured density was calculated from the weight and outer dimensions of the target cut into a certain size.
  • the bulk resistance of the target was measured by a four-probe method using a resistivity meter (Mitsubishi Oil Chemical Co., Ltd., Loresta), and as a result, it was confirmed to be 0.7 m ⁇ cm.
  • FIG. 1 is an X-ray diffraction chart of the target. From this figure, it was confirmed that hexagonal layered compounds represented by InSmO 3 and In 2 O 3 (ZnO) 3 were generated in the target.
  • the manufactured sputtering target was attached to a DC magnetron sputtering apparatus and sputtered to form an oxide semiconductor thin film having a thickness of 50 nm on a glass substrate. Abnormal discharge was not confirmed during sputtering.
  • the formed thin film was stabilized by heat treatment at 300 ° C. for 1 hour in air.
  • the crystallinity of the obtained oxide semiconductor thin film was observed by X-ray diffraction, no peak was observed, and it was confirmed to be amorphous.
  • the carrier density of the thin film was measured by Hall measurement (manufactured by Toyo Technica Co., Ltd .: REISTEST 8300). As a result, the carrier density was 3 ⁇ 10 17 / cm 3 .
  • An oxide semiconductor thin film with a thickness of 50 nm is formed in the same manner on a thermal oxide film of a hard-doped Si substrate with a 300 nm thick thermal oxide film, and has a channel length of 200 ⁇ m and a channel width of 500 ⁇ m with gold electrodes.
  • a thin film transistor element was produced.
  • InYbO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • InYbO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • InYbO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • InYbO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • InGdO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InGdO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • InDyO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InDyO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • InErO 3 and In 2 O 3 (ZnO) 3 was generated in the obtained target (FIG.
  • InLaO 3 and In 2 O 3 (ZnO) 3 hexagonal layered compounds represented by InLaO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG.
  • the target of the present invention is a transparent conductive film for various uses, such as a transparent conductive film for a liquid crystal display (LCD), a transparent conductive film for an electroluminescence (EL) display element, a transparent conductive film for a solar cell, and an oxide semiconductor thin film. It is suitable as a target for obtaining by a sputtering method.
  • a transparent conductive film for a liquid crystal display (LCD) a transparent conductive film for an electroluminescence (EL) display element
  • a transparent conductive film for a solar cell and an oxide semiconductor thin film.
  • an electrode of an organic EL element, a transparent conductive film for a semi-transmissive / semi-reflective LCD, an oxide semiconductor film for driving a liquid crystal, and an oxide semiconductor thin film for driving an organic EL element can be obtained.

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Abstract

A sintered body containing a hexagonal lamellar compound expressed as In2O3(ZnO)m (wherein m represents an integer of 2-20) and a compound expressed as InLnO3 (wherein Ln represents a trivalent lanthanoid element excluding Pr and Pm) at atomic ratios of 0.2 < In/(In + Zn) < 0.97, 0.03 < Zn/(In + Zn) < 0.8 and 0.2 < Ln/(In + Zn + Ln) < 0.5.

Description

スパッタリングターゲット及びそれからなる酸化物半導体薄膜Sputtering target and oxide semiconductor thin film comprising the same
　本発明は、焼結体、スパッタリングターゲット、酸化物半導体薄膜及び薄膜トランジスタに関する。 The present invention relates to a sintered body, a sputtering target, an oxide semiconductor thin film, and a thin film transistor.
　いくつかの金属複合酸化物からなる酸化物半導体膜は、高移動度性と可視光透過性を有することから、液晶表示装置、薄膜エレクトロルミネッセンス表示装置、電気泳動方式表示装置、粉末移動方式表示装置等のスイッチング素子、駆動回路素子等、多岐に亘る用途が検討されている。 Oxide semiconductor films made of several metal complex oxides have high mobility and visible light transmission, so that liquid crystal display devices, thin film electroluminescence display devices, electrophoretic display devices, powder transfer display devices A wide variety of applications such as switching elements and drive circuit elements are being studied.
　上記金属複合酸化物からなる酸化物半導体膜の中でも、酸化インジウム－酸化ガリウム－酸化亜鉛（ＩＧＺＯ）からなる酸化物半導体膜が最も普及している。この他に、酸化インジウム－酸化亜鉛、酸化亜鉛を添加した酸化錫（ＺＴＯ）、酸化ガリウムを添加した酸化インジウム－酸化亜鉛－酸化スズ等が知られている。これらは、製造の容易さ、価格、特性等がそれぞれ異なるので、その用途に応じて適宜使用されている。
　特に、Ｉｎ及びＧａ及びＺｎの酸化物（ＩＧＺＯ）、又はこれを主成分とする酸化物半導体膜は、アモルファスシリコン膜よりも移動度が大きいという利点があるため、注目を集めている。 Among the oxide semiconductor films made of the metal composite oxide, the oxide semiconductor film made of indium oxide-gallium oxide-zinc oxide (IGZO) is most popular. In addition, indium oxide-zinc oxide, tin oxide added with zinc oxide (ZTO), indium oxide-zinc oxide-tin oxide added with gallium oxide, and the like are known. Since these are different in ease of manufacture, price, characteristics, etc., they are used as appropriate according to their applications.
In particular, an oxide of In, Ga, and Zn (IGZO), or an oxide semiconductor film containing the oxide of In, Ga, and Zn as a main component has an advantage of higher mobility than an amorphous silicon film, and thus attracts attention.
　一般に、酸化インジウム－酸化ガリウム－酸化亜鉛からなる酸化物半導体膜形成に使用するスパッタリングターゲットは、原料粉末を混合、仮焼、粉砕、造粒、成形、焼結及び還元という工程を経て製造される。しかし、このようなスパッタリングターゲットの還元によるバルク抵抗の低減までに至る多工程は生産性を下げ、コスト増になる欠点を有していた。また、還元後の導電性は、せいぜい９０Ｓ／ｃｍ（バルク比抵抗：１１ｍΩｃｍ）程度であり、十分に低抵抗のターゲットを得ることはできなかった。 Generally, a sputtering target used for forming an oxide semiconductor film composed of indium oxide-gallium oxide-zinc oxide is manufactured through steps of mixing raw material powder, calcining, pulverizing, granulating, molding, sintering and reducing. . However, such a multi-step process up to the reduction of the bulk resistance due to the reduction of the sputtering target has the disadvantage that the productivity is lowered and the cost is increased. Further, the conductivity after the reduction was at most about 90 S / cm (bulk specific resistance: 11 mΩcm), and a sufficiently low resistance target could not be obtained.
　上述のように、酸化インジウム－酸化ガリウム－酸化亜鉛からなるスパッタリングターゲットはバルク抵抗が高く、ＤＣスパッタリング時にＩｎＧａＯ３（ＺｎＯ）ｍで表される化合物が異常成長して異常放電したり、得られる膜が不安定であったり、導電膜になってしまうおそれがあった。 As described above, the sputtering target composed of indium oxide-gallium oxide-zinc oxide has a high bulk resistance, and the compound represented by InGaO 3 (ZnO) m grows abnormally during DC sputtering, resulting in abnormal discharge or a film obtained. May be unstable or become a conductive film.
　特許文献１は、酸化インジウム－酸化亜鉛系の酸化物が、さらにランタノイド元素を含むスパッタリングターゲットを開示している。しかし、このスパッタリングターゲットを用いてキャリヤー濃度が低く、半導体特性を有する酸化物半導体を形成することは困難であった。
　特許文献２は、酸化インジウム及びランタノイド元素を含有する酸化物半導体膜を開示している。
　特許文献３は、酸化インジウム、酸化亜鉛及びランタノイド系金属酸化物を含有する有機ＥＬ素子の基板を開示する。ランタノイド系金属酸化物の配合量は全金属原子に対して０．１から２０原子％未満である。
　特許文献４は酸化亜鉛、酸化インジウム及び六方晶系に属する酸化ランタン型結晶構造を有する化合物である色むら防止剤を含むスパッタリングターゲットを開示する。 Patent Document 1 discloses a sputtering target in which an indium oxide-zinc oxide based oxide further contains a lanthanoid element. However, it has been difficult to form an oxide semiconductor having low carrier concentration and semiconductor characteristics using this sputtering target.
Patent Document 2 discloses an oxide semiconductor film containing indium oxide and a lanthanoid element.
Patent Document 3 discloses a substrate for an organic EL element containing indium oxide, zinc oxide, and a lanthanoid metal oxide. The blending amount of the lanthanoid metal oxide is 0.1 to less than 20 atomic% with respect to all metal atoms.
Patent document 4 discloses a sputtering target containing zinc oxide, indium oxide and a color unevenness preventing agent which is a compound having a lanthanum oxide type crystal structure belonging to the hexagonal system.
　本発明は、スパッタリング中に異常放電のない低抵抗なスパッタリングターゲットを提供することを目的とする。
　本発明は、キャリヤー濃度が低く、安定した半導体特性を有する酸化物半導体薄膜を提供することを目的とする。 An object of this invention is to provide the low-resistance sputtering target without an abnormal discharge during sputtering.
An object of the present invention is to provide an oxide semiconductor thin film having a low carrier concentration and stable semiconductor characteristics.
特開２００４－６８０５４号公報JP 2004-68054 A 特開２００６－１８９８３２号公報JP 2006-189832 A 特開２００４－１４６１３６号公報JP 2004-146136 A 特開２００１－１１６１３号公報JP 2001-11613 A
　本発明によれば、以下の焼結体、スパッタリングターゲット、酸化物半導体薄膜等が提供される。
１．Ｉｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数である）で表される六方晶層状化合物、及びＩｎＬｎＯ３（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）で表される化合物を含み、原子比が、０．２＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９７、０．０３＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．８、及び０．２＜（Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．５である焼結体。
２．全カチオン金属元素に対するＩｎの含有量［Ｉｎ／（全金属カチオン）：原子比］が、全金属カチオン元素に対するＬｎの含有量［Ｌｎ／（全金属カチオン）：原子比］より多い１に記載の焼結体。
３．バルク抵抗が５ｍΩｃｍ未満である１又は２に記載の焼結体。
４．１～３のいずれかに記載の焼結体からなるスパッタリングターゲット。
５．Ｉｎ、Ｚｎ及びＬｎ（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）を含み、原子比が、０．２＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９７、０．０３＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．８、及び０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．５である酸化物半導体薄膜。
６．キャリヤー密度が１０１８／ｃｍ３未満である５に記載の酸化物半導体薄膜。
７．スパッタ圧力を０．１～２Ｐａとし、酸素分圧を前記スパッタ圧力の２～２０％として、４に記載のスパッタリングターゲットをスパッタリングする酸化物半導体薄膜の製造方法。
８．前記スパッタリングを、下記式を満たす雰囲気中で行う７に記載の酸化物半導体薄膜の製造方法。
　　１０＜（酸素分圧／水の分圧）＜２００
９．５又は６に記載の酸化物半導体薄膜を用いる薄膜トランジスタ。
１０．チャンネルエッチ型である９に記載の薄膜トランジスタ。
１１．エッチストッパー型である９に記載の薄膜トランジスタ。 According to the present invention, the following sintered body, sputtering target, oxide semiconductor thin film and the like are provided.
1. A hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), and InLnO 3 (Ln is a trivalent lanthanoid element excluding Pr and Pm). The atomic ratio is 0.2 <In / (In + Zn) <0.97, 0.03 <Zn / (In + Zn) <0.8, and 0.2 <(Ln / (In + Zn + Ln) < Sintered body which is 0.5.
2. The In content [In / (total metal cation): atomic ratio] with respect to all cationic metal elements is greater than the content [Ln / (total metal cation): atomic ratio] with respect to all metallic cation elements. Sintered body.
3. 3. The sintered body according to 1 or 2, wherein the bulk resistance is less than 5 mΩcm.
4. A sputtering target comprising the sintered body according to any one of 1 to 3.
5). In, Zn and Ln (Ln is a trivalent lanthanoid element excluding Pr and Pm), the atomic ratio is 0.2 <In / (In + Zn) <0.97, 0.03 <Zn / (In + Zn) < The oxide semiconductor thin film which is 0.8 and 0.2 <Ln / (In + Zn + Ln) <0.5.
6). 6. The oxide semiconductor thin film according to 5, wherein the carrier density is less than 10 18 / cm 3 .
7). 5. A method for producing an oxide semiconductor thin film, wherein a sputtering target is sputtered at a sputtering pressure of 0.1 to 2 Pa and an oxygen partial pressure of 2 to 20% of the sputtering pressure.
8). 8. The method for producing an oxide semiconductor thin film according to 7, wherein the sputtering is performed in an atmosphere satisfying the following formula.
10 <(partial pressure of oxygen / partial pressure of water) <200
A thin film transistor using the oxide semiconductor thin film according to 9.5 or 6.
10. 10. The thin film transistor according to 9, which is a channel etch type.
11. 10. The thin film transistor according to 9, which is an etch stopper type.
　本発明によれば、スパッタリング中に異常放電のない低抵抗なスパッタリングターゲットを提供することができる。
　本発明によれば、キャリヤー濃度が低く、安定した半導体特性を有する酸化物半導体薄膜を提供することができる。 According to the present invention, it is possible to provide a low-resistance sputtering target free from abnormal discharge during sputtering.
According to the present invention, an oxide semiconductor thin film having a low carrier concentration and stable semiconductor characteristics can be provided.
本発明の薄膜トランジスタの一実施形態を示す概略断面図である。It is a schematic sectional drawing which shows one Embodiment of the thin-film transistor of this invention. 本発明の薄膜トランジスタの他の実施形態を示す概略断面図である。It is a schematic sectional drawing which shows other embodiment of the thin-film transistor of this invention. 実施例１で得られたターゲットのＸ線回折パターンを示すチャートである。2 is a chart showing an X-ray diffraction pattern of a target obtained in Example 1. FIG. 実施例２で得られたターゲットのＸ線回折パターンを示すチャートである。6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 2. 実施例３で得られたターゲットのＸ線回折パターンを示すチャートである。6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 3. 実施例４で得られたターゲットのＸ線回折パターンを示すチャートである。6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 4. 実施例５で得られたターゲットのＸ線回折パターンを示すチャートである。6 is a chart showing an X-ray diffraction pattern of a target obtained in Example 5. FIG. 実施例６で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 6. 実施例７で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 7. 実施例８で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 8. 実施例９で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 9. 実施例１０で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 10. FIG. 実施例１１で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 11. FIG. 実施例１２で得られたターゲットのＸ線回折パターンを示すチャートである。10 is a chart showing an X-ray diffraction pattern of a target obtained in Example 12. 比較例１で得られたターゲットのＸ線回折パターンを示すチャートである。6 is a chart showing an X-ray diffraction pattern of a target obtained in Comparative Example 1.
　本発明の焼結体は、Ｉｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数である）で表される六方晶層状化合物、及びＩｎＬｎＯ３（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）で表される化合物を含む。この焼結体はスパッタリングターゲットとして好適に用いることができる。
　本発明の焼結体は、さらにＩｎ２Ｏ３を含んでもよい。 The sintered body of the present invention includes a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), and InLnO 3 (Ln excludes Pr and Pm). A compound represented by a trivalent lanthanoid element). This sintered body can be suitably used as a sputtering target.
The sintered body of the present invention may further contain In 2 O 3 .
　本発明の焼結体は、酸化亜鉛をＩｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数）で表される六方晶層状化合物として含有する。これは、Ｉｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２から２０の整数）で表わされる六方晶層状化合物と、ＩｎＧａＯ３（ＺｎＯ）ｍ（式中、ｍは１から２０の整数）で表わされる六方晶層状化合物のバルク抵抗を比較した場合に、Ｇａ等の絶縁性の酸化物を含有すると、一般にバルク抵抗が大きくなるからである。 The sintered body of the present invention contains zinc oxide as a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20). This is because a hexagonal layered compound represented by In 2 O 3 (ZnO) m (where m is an integer of 2 to 20) and InGaO 3 (ZnO) m (where m is an integer of 1 to 20). This is because the bulk resistance generally increases when an insulating oxide such as Ga is contained when comparing the bulk resistance of the hexagonal layered compounds represented by the formula (1).
　尚、六方晶層状化合物とは、L.　Dupont　et　al.,　Journal　of　Solid　State　Chemistry　158,　119-133(2001)、Toshihiro　Moriga　et　al.,　J.　Am.　Ceram.　Soc.,　81(5)　1310-16(1998)等に記載された化合物である。
　本発明の焼結体に含まれる六方晶層状化合物であるＩｎ２Ｏ３（ＺｎＯ）ｍのｍは好ましくは３～７である。 The hexagonal layered compound is L. Dupont et al., Journal of Solid State Chemistry 158, 119-133 (2001), Toshihiro Moriga et al., J. Am. Ceram. Soc., 81 (5) 1310. -16 (1998).
The m of In 2 O 3 (ZnO) m that is a hexagonal layered compound contained in the sintered body of the present invention is preferably 3 to 7.
　ランタノイド元素の酸化物は絶縁性であるので、ランタノイド元素の酸化物をそのままの形態で含む焼結体は、そのバルク抵抗が大きくなる場合がある。
　本発明の焼結体は、ランタノイド元素の酸化物をＩｎＬｎＯ３（式中、Ｌｎは、Ｐｒ、Ｐｍを除く３価のランタノイド元素）で表される化合物として含有する。焼結体がランタノイド元素の酸化物をＩｎＬｎＯ３として含有することにより、絶縁性のＬｎ２Ｏ３が存在せず、結果、異常放電を低減でき、安定した成膜が可能になる。また、ランタノイド系の元素は酸素との結合力が強く、酸素欠損を作らないため、成膜時には半導体用途に適した比抵抗の薄膜が得られることになる。 Since the lanthanoid element oxide is insulative, a sintered body containing the lanthanoid element oxide as it is may have a large bulk resistance.
The sintered body of the present invention contains an oxide of a lanthanoid element as a compound represented by InLnO 3 (wherein Ln is a trivalent lanthanoid element excluding Pr and Pm). When the sintered body contains an oxide of a lanthanoid element as InLnO 3 , there is no insulating Ln 2 O 3 , and as a result, abnormal discharge can be reduced and stable film formation becomes possible. In addition, since lanthanoid elements have a strong binding force with oxygen and do not generate oxygen vacancies, a thin film having a specific resistance suitable for semiconductor applications can be obtained during film formation.
　本発明の焼結体がＩｎ２Ｏ３を含むとき、Ｌｎ2Ｏ３が酸化インジウム（Ｉｎ２Ｏ３）中にドーピングする形態となって、絶縁性のＬｎ２Ｏ３が存在せず、結果、安定したスパッタリングが可能となる。 When the sintered body of the present invention contains In 2 O 3 , Ln 2 O 3 is doped into indium oxide (In 2 O 3 ), and there is no insulating Ln 2 O 3 , resulting Stable sputtering becomes possible.
　また、ＩｎＬｎＯ３で表される化合物が酸化インジウム（Ｉｎ２Ｏ３）にドーピングすることにより、焼結体中の結晶の異常成長を抑制することができる。これによりスパッタリング時の異常放電が抑えられ、表面平滑性に優れた薄膜を形成することができる。 In addition, when the compound represented by InLnO 3 is doped into indium oxide (In 2 O 3 ), abnormal growth of crystals in the sintered body can be suppressed. Thereby, abnormal discharge at the time of sputtering is suppressed, and a thin film having excellent surface smoothness can be formed.
　焼結体中の結晶粒子は、例えば粒径が５μｍ、好ましくは３μｍ未満の大きさに微細化される。 The crystal particles in the sintered body are refined to a size of, for example, a particle size of 5 μm, preferably less than 3 μm.
　Ｌｎは、Ｐｒ、Ｐｍを除く３価のランタノイド元素である、即ち、Ｌａ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕである。Ｐｒ及びＰｍを含有する焼結体から得られる薄膜は放射能を有する恐れがある。 Ln is a trivalent lanthanoid element excluding Pr and Pm, that is, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. A thin film obtained from a sintered body containing Pr and Pm may have radioactivity.
　ＩｎＬｎＯ３の具体例としては、ＩｎＬａＯ３、ＩｎＮｄＯ３、ＩｎＳｍＯ３、ＩｎＥｕＯ３、ＩｎＧｄＯ３、ＩｎＴｂＯ３、ＩｎＤｙＯ３、ＩｎＨｏＯ３、ＩｎＥｒＯ３、ＩｎＴｍＯ３、ＩｎＹｂＯ３、ＩｎＬｕＯ３等が挙げられ、取り扱いが容易であることから、好ましくはＩｎＳｍＯ３、ＩｎＧｄＯ３、ＩｎＤｙＯ３、ＩｎＥｒＯ３、ＩｎＹｂＯ３等を用いる。 Examples of InLnO 3, InLaO 3, InNdO 3 , InSmO 3, InEuO 3, InGdO 3, InTbO 3, InDyO 3, InHoO 3, InErO 3, InTmO 3, InYbO 3, InLuO 3 and the like, to handle Since it is easy, InSmO 3 , InGdO 3 , InDyO 3 , InErO 3 , InYbO 3 or the like is preferably used.
　本発明の焼結体において、インジウム、亜鉛及びランタノイド元素の原子比は、
　０．２＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９７
０．０３＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．８、及び
　０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．５であり、
　好ましくは
０．２５＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９５、
０．０５＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．７５、及び
　０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．４５であり、
　より好ましくは
０．２５＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９、
　０．１＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．７５、及び
　０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．４である。
　上記原子比は、ＩＣＰ発光分析により求めることができる。 In the sintered body of the present invention, the atomic ratio of indium, zinc and lanthanoid elements is
0.2 <In / (In + Zn) <0.97
0.03 <Zn / (In + Zn) <0.8, and 0.2 <Ln / (In + Zn + Ln) <0.5,
Preferably 0.25 <In / (In + Zn) <0.95,
0.05 <Zn / (In + Zn) <0.75, and 0.2 <Ln / (In + Zn + Ln) <0.45,
More preferably, 0.25 <In / (In + Zn) <0.9,
0.1 <Zn / (In + Zn) <0.75, and 0.2 <Ln / (In + Zn + Ln) <0.4.
The atomic ratio can be obtained by ICP emission analysis.
　原子比Ｉｎ／（Ｉｎ＋Ｚｎ）が０．２以下の場合、得られる薄膜が導電性になったり、薄膜の耐久性が乏しくなるおそれがある。また、原子比Ｉｎ／（Ｉｎ＋Ｚｎ）が０．９７以上の場合、得られる薄膜が導電性になったり、薄膜が結晶化するおそれがある。 When the atomic ratio In / (In + Zn) is 0.2 or less, the resulting thin film may become conductive or the durability of the thin film may be poor. Further, when the atomic ratio In / (In + Zn) is 0.97 or more, the obtained thin film may become conductive or the thin film may be crystallized.
　原子比Ｚｎ／（Ｉｎ＋Ｚｎ）が０．０３以下の場合、得られる薄膜が導電性になったり、薄膜が結晶化するおそれがある。また、Ｚｎ／（Ｉｎ＋Ｚｎ）が０．８以上の場合、得られる薄膜が導電性になったり、薄膜の耐久性が乏しくなるおそれがある。 When the atomic ratio Zn / (In + Zn) is 0.03 or less, the resulting thin film may become conductive or the thin film may crystallize. Moreover, when Zn / (In + Zn) is 0.8 or more, the obtained thin film may become conductive, or the durability of the thin film may be poor.
　原子比Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）が０．２以下の場合、得られる薄膜が導電性となるおそれがある。また、原子比Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）が０．５以上の場合、得られる薄膜はキャリヤーが殆ど無くなって絶縁性の膜となり、半導体として機能しないおそれがある。 If the atomic ratio Ln / (In + Zn + Ln) is 0.2 or less, the resulting thin film may become conductive. Further, when the atomic ratio Ln / (In + Zn + Ln) is 0.5 or more, the obtained thin film has almost no carriers and becomes an insulating film, which may not function as a semiconductor.
　本発明の焼結体は、好ましくは全カチオン金属元素に対するＩｎの含有量［Ｉｎ／（全金属カチオン）：原子比］が、全金属カチオン元素に対するＬｎの含有量［Ｌｎ／（全金属カチオン）：原子比］より多い。即ち、焼結体は好ましくは下記式を満たす。
　Ｉｎ／（全金属カチオン）＞Ｌｎ／（全金属カチオン） The sintered body of the present invention preferably has an In content [In / (total metal cation): atomic ratio] to the total cation metal element, and an Ln content [Ln / (total metal cation) to the total metal cation element]. : Atomic ratio]. That is, the sintered body preferably satisfies the following formula.
In / (all metal cations)> Ln / (all metal cations)
　焼結体が上記式を満たすことで、焼結体中の酸化ランタノイド（Ｌｎ２Ｏ３）は、ＩｎＬｎＯ３となって、焼結体の導電性を向上させることができる。これにより焼結体のバルク抵抗を低減でき、安定したスパッタリングが可能となる。一方、焼結体が上記式を満たさない場合、焼結体中のＬｎ２Ｏ３は、ＩｎＬｎＯ３とならず、絶縁性のＬｎ２Ｏ３の形態で存在しスパッタリング中に異常放電するおそれがある。 When the sintered body satisfies the above formula, the lanthanoid oxide (Ln 2 O 3 ) in the sintered body becomes InLnO 3 and the conductivity of the sintered body can be improved. Thereby, the bulk resistance of a sintered compact can be reduced and stable sputtering becomes possible. On the other hand, when the sintered body does not satisfy the above formula, Ln 2 O 3 in the sintered body does not become InLnO 3 but exists in the form of insulating Ln 2 O 3 , which may cause abnormal discharge during sputtering. is there.
　本発明の焼結体は、好ましくはバルク抵抗が５ｍΩｃｍ未満であり、より好ましくは３ｍΩｃｍ以下、さらに好ましくは１ｍΩｃｍ以下である。
　焼結体のバルク抵抗が５ｍΩｃｍ以上の場合、スパッタリング中に異常放電したり、異物（ノジュール）が発生するおそれがある。
　Ｉｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数である）で表される六方晶層状化合物、ＩｎＬｎＯ３で表される化合物、場合によっては、ＩｎＬｎＯ３（ＺｎＯ）ｍで表される六方晶層状化合物として含有していてもよい。
　焼結体中の酸化ランタノイド（Ｌｎ２Ｏ３）がＬｎ２Ｏ３の形態で存在する場合、絶縁性の高いＬｎ２Ｏ３は、異常放電の原因となり、成膜された膜中に異物を発生させたり、薄膜の表面精度を低下させたりする場合がある。 The sintered body of the present invention preferably has a bulk resistance of less than 5 mΩcm, more preferably 3 mΩcm or less, and even more preferably 1 mΩcm or less.
When the bulk resistance of the sintered body is 5 mΩcm or more, abnormal discharge or foreign matter (nodules) may occur during sputtering.
A hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), a compound represented by InLnO 3 , and in some cases, InLnO 3 (ZnO) m You may contain as a hexagonal layered compound represented.
When the lanthanoid oxide (Ln 2 O 3 ) in the sintered body is present in the form of Ln 2 O 3 , the highly insulating Ln 2 O 3 causes abnormal discharge, which causes foreign matter in the deposited film. May occur, or the surface accuracy of the thin film may be reduced.
　本発明の焼結体は、Ｉｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数である）で表される六方晶層状化合物、ＩｎＬｎＯ３（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）で表される化合物、及び任意にＩｎ２Ｏ３から実質的になっていてもよく、これら化合物のみからなってもよい。「実質的になる」とは、本発明の焼結体がＩｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数である）で表される六方晶層状化合物、ＩｎＬｎＯ３（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）で表される化合物、及び任意にＩｎ２Ｏ３のみからなり、さらに以下の成分を含みうることである。 The sintered body of the present invention is a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), InLnO 3 (Ln excludes Pr and Pm 3 A valent lanthanoid element), and optionally In 2 O 3 , or only these compounds. "Substantially" means that the sintered body of the present invention is a hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), InLnO 3 ( Ln consists of a compound represented by a trivalent lanthanoid element excluding Pr and Pm), and optionally In 2 O 3 , and may further contain the following components.
　本発明の焼結体は、微量不純物として、正４価の金属酸化物を含んでもよい。
　正４価の金属酸化物は、酸化インジウム中でドーピングによるキャリヤーの発生がなく、酸化物半導体薄膜のキャリヤー制御を容易にすることができる。
　上記正４価の金属酸化物は、好ましくはＣｅＯ２、ＧｅＯ２、ＺｒＯ２、ＳｎＯ２、ＴｉＯ２等であり、得られる酸化物半導体薄膜の安定性の観点から、より好ましくはＣｅＯ２、ＧｅＯ２及びＺｒＯ２である。 The sintered body of the present invention may contain a positive tetravalent metal oxide as a trace impurity.
The positive tetravalent metal oxide does not generate carriers due to doping in indium oxide, and can facilitate carrier control of the oxide semiconductor thin film.
The positive tetravalent metal oxide is preferably CeO 2 , GeO 2 , ZrO 2 , SnO 2 , TiO 2 or the like, and more preferably CeO 2 , GeO from the viewpoint of the stability of the obtained oxide semiconductor thin film. 2 and ZrO 2 .
　正４価の金属酸化物の含有量は例えば５０～３０００ｐｐｍであり、好ましくは１００～２０００ｐｐｍ、より好ましくは２００～１０００ｐｐｍである。
　正４価の金属酸化物の含有量が５０ｐｐｍ未満では、添加によって得られる効果が小さいおそれがある。一方、正４価の金属酸化物の含有量が３０００ｐｐｍ超では、得られる薄膜のキャリヤー制御が困難となって、薄膜が導電性を有するようになり、半導体特性であるオフ電流値が大きくなって薄膜が安定しないおそれがある。 The content of the positive tetravalent metal oxide is, for example, 50 to 3000 ppm, preferably 100 to 2000 ppm, more preferably 200 to 1000 ppm.
If the content of the positive tetravalent metal oxide is less than 50 ppm, the effect obtained by addition may be small. On the other hand, if the content of the positive tetravalent metal oxide exceeds 3000 ppm, it becomes difficult to control the carrier of the obtained thin film, the thin film becomes conductive, and the off-current value, which is a semiconductor characteristic, increases. The thin film may not be stable.
　本発明の焼結体は、例えば、酸化インジウム（Ｉｎ２Ｏ３）、酸化亜鉛（ＺｎＯ）及び酸化ランタノイド（Ｌｎ２Ｏ３）の各粉体を混合し、この混合物を粉砕、焼結することにより製造できる。
　原料粉について、酸化インジウム粉の比表面積を８～１０ｍ２／ｇ、酸化亜鉛粉の比表面積を２～４ｍ２／ｇ、酸化ランタノイドの比表面積を５～１５ｍ２／ｇとすることが好ましい。又は、酸化インジウム粉のメジアン径を１～２μｍ、酸化亜鉛粉のメジアン径を０．８～１．６μｍ、酸化ランタノイドのメジアン径を１～２μｍとすることが好ましい。 In the sintered body of the present invention, for example, indium oxide (In 2 O 3 ), zinc oxide (ZnO) and lanthanoid oxide (Ln 2 O 3 ) powders are mixed, and the mixture is pulverized and sintered. Can be manufactured.
Regarding the raw material powder, the specific surface area of the indium oxide powder is preferably 8 to 10 m 2 / g, the specific surface area of the zinc oxide powder is 2 to 4 m 2 / g, and the specific surface area of the lanthanide oxide is preferably 5 to 15 m 2 / g. Alternatively, the median diameter of the indium oxide powder is preferably 1 to 2 μm, the median diameter of the zinc oxide powder is 0.8 to 1.6 μm, and the median diameter of the lanthanide oxide is preferably 1 to 2 μm.
　原料粉において、酸化インジウム粉、酸化亜鉛粉及び酸化ランタノイド粉の配合比（酸化インジウム粉：酸化亜鉛粉：酸化ランタノイド粉）は、各元素の原子比が上述した好ましい原子比となるように調製すればよい。
　尚、酸化インジウム粉、酸化亜鉛粉及び酸化ランタノイド粉を含有する混合粉体を使用する限り、焼結体の特性を改善する他の成分を添加してもよい。 In the raw material powder, the mixing ratio of indium oxide powder, zinc oxide powder, and lanthanoid oxide powder (indium oxide powder: zinc oxide powder: lanthanoid oxide powder) is prepared so that the atomic ratio of each element becomes the above-mentioned preferable atomic ratio. That's fine.
In addition, as long as the mixed powder containing indium oxide powder, zinc oxide powder, and lanthanoid oxide powder is used, other components that improve the characteristics of the sintered body may be added.
　混合粉体は、例えば、湿式媒体撹拌ミルを使用して混合粉砕する。このとき、粉砕後の比表面積が原料混合粉体の比表面積より１．５～２．５ｍ２／ｇ増加する程度か、又は粉砕後の平均メジアン径が０．６～１μｍとなる程度に粉砕することが好ましい。このように調整した原料粉を使用することにより、仮焼工程を全く必要とせずに、高密度（例えば相対密度が９５％以上）の酸化物焼結体を得ることができ、還元工程も不要にできる。 The mixed powder is mixed and ground using, for example, a wet medium stirring mill. At this time, pulverization is performed so that the specific surface area after pulverization is 1.5 to 2.5 m 2 / g higher than the specific surface area of the raw material mixed powder, or the average median diameter after pulverization is 0.6 to 1 μm. It is preferable to do. By using the raw material powder thus adjusted, it is possible to obtain an oxide sintered body having a high density (for example, a relative density of 95% or more) without requiring any calcination process, and no reduction process is required. Can be.
　尚、原料混合粉体の比表面積の増加分が１．５ｍ２／ｇ未満又は粉砕後の原料混合粉の平均メジアン径が１μｍを超えると、焼結密度が十分に大きくならない場合がある。一方、原料混合粉体の比表面積の増加分が２．５ｍ２／ｇを超える場合又は粉砕後の平均メジアン径が０．６μｍ未満にすると、粉砕時の粉砕器機等からのコンタミ（不純物混入量）が増加する場合がある。 In addition, when the increase in the specific surface area of the raw material mixed powder is less than 1.5 m 2 / g or the average median diameter of the raw material mixed powder after pulverization exceeds 1 μm, the sintered density may not be sufficiently increased. On the other hand, if the increase in the specific surface area of the raw material mixed powder exceeds 2.5 m 2 / g, or if the average median diameter after pulverization is less than 0.6 μm, contamination from the pulverizer during pulverization (impurity contamination amount) ) May increase.
　ここで、各粉体の比表面積はＢＥＴ法で測定できる。各粉体の粒度分布のメジアン径は、粒度分布計で測定できる。これらの値は、粉体を乾式粉砕法、湿式粉砕法等により粉砕することにより調整できる。 Here, the specific surface area of each powder can be measured by the BET method. The median diameter of the particle size distribution of each powder can be measured with a particle size distribution meter. These values can be adjusted by pulverizing the powder by a dry pulverization method, a wet pulverization method or the like.
　粉砕工程後の原料をスプレードライヤー等で乾燥した後、成形する。成形は公知の方法、例えば、加圧成形、冷間静水圧加圧が採用できる。 The raw material after the pulverization process is dried with a spray dryer or the like and then molded. For forming, a known method such as pressure forming or cold isostatic pressing can be employed.
　次いで、得られた成形体を焼結して焼結体を得る。焼結は、１３５０～１４５０℃で２～２０時間焼結することが好ましい。１３５０℃未満では、密度が向上せず、また、１４５０℃を超えると亜鉛が蒸散し、焼結体の組成が変化したり、蒸散により焼結体中にボイド（空隙）が発生したりする場合がある。
　焼結は酸素を流通することにより酸素雰囲気中で焼結するか、加圧下にて焼結するのがよい。これにより亜鉛の蒸散を抑えることができ、ボイド（空隙）のない焼結体が得られる。 Next, the obtained molded body is sintered to obtain a sintered body. Sintering is preferably performed at 1350 to 1450 ° C. for 2 to 20 hours. When the temperature is lower than 1350 ° C., the density is not improved. When the temperature exceeds 1450 ° C., zinc is evaporated, the composition of the sintered body is changed, or voids (voids) are generated in the sintered body due to the evaporation. There is.
Sintering is preferably performed in an oxygen atmosphere by circulating oxygen or under pressure. Thereby, transpiration of zinc can be suppressed, and a sintered body free from voids (voids) can be obtained.
　得られた焼結体を、研磨等の加工を施すことによりスパッタリングターゲットとすることができる。具体的には、焼結体を、例えば、平面研削盤で研削して表面粗さＲａを５μｍ以下とする。さらに、ターゲットのスパッタ面に鏡面加工を施して、平均表面粗さＲａが１０００オングストローム以下としてもよい。この鏡面加工（研磨）は機械的な研磨、化学研磨、メカノケミカル研磨（機械的な研磨と化学研磨の併用）等の、すでに知られている研磨技術を用いることができる。例えば、固定砥粒ポリッシャー（ポリッシュ液：水）で＃２０００以上にポリッシングしたり、又は遊離砥粒ラップ（研磨材：ＳｉＣペースト等）にてラッピング後、研磨材をダイヤモンドペーストに換えてラッピングすることによって得ることができる。このような研磨方法には特に制限はない。 The obtained sintered body can be used as a sputtering target by performing processing such as polishing. Specifically, the sintered body is ground by, for example, a surface grinder so that the surface roughness Ra is 5 μm or less. Further, the sputter surface of the target may be mirror-finished so that the average surface roughness Ra is 1000 angstroms or less. For this mirror finishing (polishing), a known polishing technique such as mechanical polishing, chemical polishing, mechanochemical polishing (a combination of mechanical polishing and chemical polishing) can be used. For example, polishing to # 2000 or more with a fixed abrasive polisher (polishing liquid: water) or lapping with loose abrasive lapping (abrasive: SiC paste, etc.), and then lapping by changing the abrasive to diamond paste Can be obtained by: Such a polishing method is not particularly limited.
　得られたスパッタリングターゲットをバッキングプレートへボンディングすることにより、各種装置に装着して使用できる。物理成膜法としては、例えば、スパッタリング法、ＰＬＤ（パルスレーザーディポジション）法、真空蒸着法、イオンプレーティング法等が挙げられる。 By bonding the obtained sputtering target to a backing plate, it can be used by being mounted on various devices. Examples of the physical film forming method include a sputtering method, a PLD (pulse laser deposition) method, a vacuum deposition method, and an ion plating method.
　尚、スパッタリングターゲットの清浄処理には、エアーブローや流水洗浄等を使用できる。エアーブローで異物を除去する際には、ノズルの向い側から集塵機で吸気を行なうとより有効に除去できる。
　エアーブローや流水洗浄の他に、超音波洗浄等を行なうこともできる。超音波洗浄では、周波数２５～３００ＫＨｚの間で多重発振させて行なう方法が有効である。例えば周波数２５～３００ＫＨｚの間で、２５ＫＨｚ刻みに１２種類の周波数を多重発振させて超音波洗浄を行なうのがよい。 In addition, air blow, running water washing | cleaning, etc. can be used for the cleaning process of a sputtering target. When removing foreign matter by air blow, it is possible to remove the foreign matter more effectively by suctioning with a dust collector from the opposite side of the nozzle.
In addition to air blow and running water cleaning, ultrasonic cleaning and the like can also be performed. For ultrasonic cleaning, a method of performing multiple oscillation at a frequency of 25 to 300 KHz is effective. For example, it is preferable to perform ultrasonic cleaning by multiplying twelve types of frequencies in 25 KHz increments between frequencies of 25 to 300 KHz.
　本発明の酸化物半導体薄膜は、Ｉｎ、Ｚｎ及びＬｎ（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）を含み、これらの原子比は、
　０．２＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９７
０．０３＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．８、及び
　０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．５であり、
　好ましくは
０．２５＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９５、
０．０５＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．７５、及び
　０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．４５であり、
　より好ましくは
０．２５＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９、
　０．１＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．７５、及び
　０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．４である。 The oxide semiconductor thin film of the present invention contains In, Zn, and Ln (Ln is a trivalent lanthanoid element excluding Pr and Pm), and the atomic ratio thereof is
0.2 <In / (In + Zn) <0.97
0.03 <Zn / (In + Zn) <0.8, and 0.2 <Ln / (In + Zn + Ln) <0.5,
Preferably 0.25 <In / (In + Zn) <0.95,
0.05 <Zn / (In + Zn) <0.75, and 0.2 <Ln / (In + Zn + Ln) <0.45,
More preferably, 0.25 <In / (In + Zn) <0.9,
0.1 <Zn / (In + Zn) <0.75, and 0.2 <Ln / (In + Zn + Ln) <0.4.
　本発明の酸化物半導体薄膜は、キャリヤー濃度が低く、安定した半導体特性を有する。 The oxide semiconductor thin film of the present invention has a low carrier concentration and stable semiconductor characteristics.
　原子比Ｉｎ／（Ｉｎ＋Ｚｎ）が０．２以下の場合、薄膜が導電性になったり、薄膜の耐久性が乏しくなるおそれがある。また、原子比Ｉｎ／（Ｉｎ＋Ｚｎ）が０．９７以上の場合、薄膜が導電性になったり、薄膜が結晶化するおそれがある。 If the atomic ratio In / (In + Zn) is 0.2 or less, the thin film may become conductive or the durability of the thin film may be poor. Further, when the atomic ratio In / (In + Zn) is 0.97 or more, the thin film may become conductive or the thin film may be crystallized.
　原子比Ｚｎ／（Ｉｎ＋Ｚｎ）が０．０３以下の場合、薄膜が導電性になったり、薄膜が結晶化するおそれがある。また、Ｚｎ／（Ｉｎ＋Ｚｎ）が０．８以上の場合、薄膜が導電性になったり、薄膜の耐久性が乏しくなるおそれがある。 When the atomic ratio Zn / (In + Zn) is 0.03 or less, the thin film may become conductive or the thin film may crystallize. Moreover, when Zn / (In + Zn) is 0.8 or more, the thin film may become conductive or the durability of the thin film may be poor.
　原子比Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）が０．２以下の場合、薄膜が導電性となるおそれがある。また、原子比Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）が０．５以上の場合、薄膜はキャリヤーが殆ど無くなって絶縁性の膜となり、半導体として機能しないおそれがある。 If the atomic ratio Ln / (In + Zn + Ln) is 0.2 or less, the thin film may become conductive. When the atomic ratio Ln / (In + Zn + Ln) is 0.5 or more, the thin film has almost no carriers and becomes an insulating film, which may not function as a semiconductor.
　本発明の酸化物半導体薄膜のキャリヤー密度は、好ましくは１０１８／ｃｍ３未満であり、より好ましくは１０１５／ｃｍ３以上１０１８／ｃｍ３未満であり、さらに好ましくは、１０１５／ｃｍ３以上５×１０１７／ｃｍ３未満である。尚、酸化物半導体薄膜のキャリヤー密度の下限は特に限定されないが、例えば１０１２／ｃｍ３以上である。酸化物半導体薄膜は本発明の組成割合にすることにより上記キャリア濃度を達成することができる。 The carrier density of the oxide semiconductor thin film of the present invention is preferably less than 10 18 / cm 3 , more preferably 10 15 / cm 3 or more and less than 10 18 / cm 3 , and even more preferably 10 15 / cm 3. This is less than 5 × 10 17 / cm 3 . Note that the lower limit of the carrier density of the oxide semiconductor thin film is not particularly limited, but is, for example, 10 12 / cm 3 or more. The carrier concentration of the oxide semiconductor thin film can be achieved by setting the composition ratio of the present invention.
　酸化物半導体薄膜のキャリヤー密度を１０１８／ｃｍ３未満とすることにより、酸化物半導体薄膜は半導体として十分に機能することができる。
　上記キャリヤー密度は、例えば、後述する酸化物半導体薄膜の成膜時の酸素分圧等で調整できる。 When the carrier density of the oxide semiconductor thin film is less than 10 18 / cm 3 , the oxide semiconductor thin film can sufficiently function as a semiconductor.
The carrier density can be adjusted, for example, by an oxygen partial pressure at the time of forming an oxide semiconductor thin film described later.
　本発明の酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＞１０６、電界効果移動度＞２ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＜１０Ｖ、及びＳ値＜５であるとよい。これらの条件を満たせば、酸化物半導体薄膜は、液晶表示用の駆動用薄膜トランジスタ、有機ＥＬ用の駆動用薄膜トランジスタ等として十分機能することができる。 The semiconductor characteristics of the oxide semiconductor thin film of the present invention are preferably On / Off value> 10 6 , field-effect mobility> 2 cm 2 / V · sec, threshold voltage (Vth) <10 V, and S value <5. If these conditions are satisfied, the oxide semiconductor thin film can sufficiently function as a driving thin film transistor for liquid crystal display, a driving thin film transistor for organic EL, or the like.
　本発明の酸化物半導体薄膜は、スパッタ圧力を０．１～２Ｐａとし、酸素分圧をスパッタ圧力の２～２０％として本発明のスパッタリングターゲットをスパッタリングすることにより成膜できる。 The oxide semiconductor thin film of the present invention can be formed by sputtering the sputtering target of the present invention at a sputtering pressure of 0.1 to 2 Pa and an oxygen partial pressure of 2 to 20% of the sputtering pressure.
　スパッタ圧力は０．１～２Ｐａであり、好ましくは０．２～１Ｐａである。
　スパッタ圧力が０．１Ｐａ未満の場合、高真空での成膜となり、スパッタ速度が低下したり、高真空にするためにコストが高くなるおそれがある。一方、スパッタ圧力が２Ｐａ超の場合、スパッタのプラズマが安定せず、スパッタ速度が低下したり、得られる薄膜の膜質が低下するおそれがある。 The sputtering pressure is 0.1 to 2 Pa, preferably 0.2 to 1 Pa.
When the sputtering pressure is less than 0.1 Pa, the film formation is performed at a high vacuum, and the sputtering rate may decrease, or the cost may increase due to the high vacuum. On the other hand, when the sputtering pressure exceeds 2 Pa, the sputtering plasma may not be stable, and the sputtering rate may decrease, or the film quality of the resulting thin film may decrease.
　酸素分圧は、スパッタ圧力の２～２０％であり、好ましくは３～１０％であり、より好ましくは４～８％である。
　酸素は得られる薄膜の酸素欠損を制御することから、上述のようにスパッタ中の酸素分圧を厳密に制御する必要がある。酸素分圧がスパッタ圧力の２％未満の場合、得られる薄膜が導電性薄膜となったり、半導体特性であるオフ電流が増加するおそれがある。また、酸素分圧がスパッタ圧力の２０％超の場合、薄膜が大量の酸素を取り込み、半導体特性である電界効果移動度が低下するおそれがある。 The oxygen partial pressure is 2 to 20%, preferably 3 to 10%, more preferably 4 to 8% of the sputtering pressure.
Since oxygen controls oxygen vacancies in the resulting thin film, it is necessary to strictly control the oxygen partial pressure during sputtering as described above. When the oxygen partial pressure is less than 2% of the sputtering pressure, the resulting thin film may become a conductive thin film, or the off-current that is a semiconductor characteristic may increase. Further, when the oxygen partial pressure exceeds 20% of the sputtering pressure, the thin film takes in a large amount of oxygen, and there is a possibility that the field effect mobility, which is a semiconductor characteristic, is lowered.
　酸素分圧は、スパッタ圧力の２～２０％であれば特に制限されないが、スパッタリングターゲットのランタノイド元素の含有量により、最適な酸素分圧は変化する。
　ランタノイド元素（Ｐｒ、Ｐｍを除く３価のランタノイド元素）は、通常、成膜時に薄膜中に酸素を取り込みやすくし、薄膜中の酸素欠損量を少なくする効果を有する。よって、ターゲットのランタノイド元素の含有量が少ない場合には、スパッタ中の酸素分圧を高くし、ランタノイド元素の含有量が多い場合には、スパッタ中の酸素分圧を低くするとよい。 The oxygen partial pressure is not particularly limited as long as it is 2 to 20% of the sputtering pressure, but the optimum oxygen partial pressure varies depending on the content of the lanthanoid element in the sputtering target.
Lanthanoid elements (trivalent lanthanoid elements excluding Pr and Pm) usually have an effect of facilitating incorporation of oxygen into the thin film during film formation and reducing the amount of oxygen vacancies in the thin film. Therefore, when the target lanthanoid element content is low, the oxygen partial pressure during sputtering is increased, and when the lanthanoid element content is high, the oxygen partial pressure during sputtering is preferably decreased.
　酸化物半導体薄膜に水が混入すると、オフ電流を増加させたり、電界効果移動度を低下させたり、耐久性が劣化するおそれがある。従って、上記スパッタリングは、好ましくは水の分圧及び酸素分圧が１０＜（酸素分圧／水の分圧）＜２００を満たす雰囲気中で行う。
　上記式は、より好ましくは１５＜（酸素分圧／水の分圧）＜１５０であり、さらに好ましくは２０＜（酸素分圧／水の分圧）＜１００である。 When water is mixed in the oxide semiconductor thin film, off current may be increased, field effect mobility may be decreased, and durability may be deteriorated. Therefore, the sputtering is preferably performed in an atmosphere where the partial pressure of water and the partial pressure of oxygen satisfy 10 <(oxygen partial pressure / water partial pressure) <200.
The above formula is more preferably 15 <(oxygen partial pressure / water partial pressure) <150, and more preferably 20 <(oxygen partial pressure / water partial pressure) <100.
　酸素分圧／水の分圧が１０以下の場合、得られる酸化物半導体薄膜の耐久性が低下したり、オフ電流が増大したり、電界効果移動度を低下したりするおそれがある。一方、酸素分圧／水の分圧が２００以上の場合、水分子の排気にコストかかるため、生産性が低下するおそれがある。 When the oxygen partial pressure / water partial pressure is 10 or less, durability of the resulting oxide semiconductor thin film may be reduced, off-current may be increased, or field-effect mobility may be reduced. On the other hand, when the oxygen partial pressure / water partial pressure is 200 or more, the cost of exhausting water molecules is high, and thus productivity may be reduced.
　本発明の薄膜トランジスタは上記の酸化物半導体薄膜を用いる。
　図１は、本発明の薄膜トランジスタの一実施形態を示す概略断面図である。
　薄膜トランジスタ１はチャンネルエッチ型薄膜トランジスタである。薄膜トランジスタ１は、基板１０及び絶縁膜３０の間にゲート電極２０を挟持しており、ゲート絶縁膜３０上には本発明の酸化物半導体薄膜４０が活性層として積層されている。さらに、酸化物半導体薄膜４０の端部付近を覆うようにしてソース電極５０及びドレイン電極５２がそれぞれ設けられている。酸化物半導体薄膜４０、ソース電極５０及びドレイン電極５２で囲まれた部分にチャンネル部６０を形成している。 The thin film transistor of the present invention uses the above oxide semiconductor thin film.
FIG. 1 is a schematic cross-sectional view showing an embodiment of the thin film transistor of the present invention.
The thin film transistor 1 is a channel etch type thin film transistor. In the thin film transistor 1, the gate electrode 20 is sandwiched between the substrate 10 and the insulating film 30, and the oxide semiconductor thin film 40 of the present invention is stacked on the gate insulating film 30 as an active layer. Further, a source electrode 50 and a drain electrode 52 are provided so as to cover the vicinity of the end of the oxide semiconductor thin film 40. A channel portion 60 is formed in a portion surrounded by the oxide semiconductor thin film 40, the source electrode 50 and the drain electrode 52.
　図２は、本発明の薄膜トランジスタの他の実施形態を示す概略断面図である。尚、上述した薄膜トランジスタ１と同じ構成部材には同じ番号を付し、その説明を省略する。
　薄膜トランジスタ２は、エッチストッパー型の薄膜トランジスタである。薄膜トランジスタ２は、チャンネル部６０を覆うようにエッチストッパー７０が形成されている点を除き、上述した薄膜トランジスタ１と同じ構成である。酸化物半導体薄膜４０の端部付近及びエッチストッパー７０の端部付近を覆うようにしてソース電極５０及びドレイン電極５２がそれぞれ設けられている。
　尚、本発明の薄膜トランジスタは、チャンネルエッチ型やエッチストッパー型トランジスタに限定されず、本技術分野で公知の素子構成を採用できる。 FIG. 2 is a schematic cross-sectional view showing another embodiment of the thin film transistor of the present invention. In addition, the same number is attached | subjected to the same structural member as the thin-film transistor 1 mentioned above, and the description is abbreviate | omitted.
The thin film transistor 2 is an etch stopper type thin film transistor. The thin film transistor 2 has the same configuration as the thin film transistor 1 described above except that an etch stopper 70 is formed so as to cover the channel portion 60. A source electrode 50 and a drain electrode 52 are provided so as to cover the vicinity of the end of the oxide semiconductor thin film 40 and the vicinity of the end of the etch stopper 70.
Note that the thin film transistor of the present invention is not limited to a channel etch type or etch stopper type transistor, and an element configuration known in this technical field can be adopted.
　以下、本発明を実施例を基に詳細に説明するが、本発明はその要旨を越えない限り、以下の実施例に限定されない。 Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to the following examples unless it exceeds the gist.
実施例１
［スパッタリングターゲットの製造］
　原料粉として、酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉を重量比でほぼ７０：２５：５（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．８９、Ｓｍ／（Ｉｎ＋Ｓｍ＋Ｚｎ）＝０．２１）となるように秤量し、湿式媒体攪拌ミルを使用して混合粉砕した。 Example 1
[Manufacture of sputtering target]
As raw material powder, indium oxide powder, samarium oxide and zinc oxide powder are weighed so that the weight ratio is approximately 70: 25: 5 (In / (In + Zn) = 0.89, Sm / (In + Sm + Zn) = 0.21). And then mixed and ground using a wet medium stirring mill.
　得られた混合粉をスプレードライヤで乾燥し、金型に充填して加圧成形した。得られた成形体を酸素雰囲気中で１４２０℃で２０時間焼結して焼結体とし、さらに切削加工してスパッタリングターゲットとした。
　得られたターゲットの相対密度（混合した酸化物の密度を重量配分して得られる理論密度を実測密度で割った値）は、９５％以上であることを確認した。尚、実測密度は一定の大きさに切り出したターゲットの重量と外形寸法より算出した。 The obtained mixed powder was dried with a spray dryer, filled in a mold, and press-molded. The obtained molded body was sintered in an oxygen atmosphere at 1420 ° C. for 20 hours to obtain a sintered body, and further cut to obtain a sputtering target.
It was confirmed that the relative density of the target obtained (the value obtained by dividing the density of the mixed oxide by weight and divided by the actually measured density) was 95% or more. The measured density was calculated from the weight and outer dimensions of the target cut into a certain size.
　ターゲットのバルク抵抗を、抵抗率計（三菱油化製、ロレスタ）を使用して四探針法で測定した結果、０．７ｍΩｃｍであることを確認した。
　加えて、ターゲットについてＩＣＰ発光分析をしたところ、原子比はＩｎ／（Ｉｎ＋Ｚｎ）＝０．８９、Ｓｍ／（Ｉｎ＋Ｓｍ＋Ｚｎ）＝０．２１であることを確認した。 The bulk resistance of the target was measured by a four-probe method using a resistivity meter (Mitsubishi Oil Chemical Co., Ltd., Loresta), and as a result, it was confirmed to be 0.7 mΩcm.
In addition, ICP emission analysis of the target confirmed that the atomic ratios were In / (In + Zn) = 0.89 and Sm / (In + Sm + Zn) = 0.21.
　このターゲットをＸ線回折により分析した。図１はターゲットのＸ線回折チャートである。この図からターゲット中にＩｎＳｍＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認できた。 This target was analyzed by X-ray diffraction. FIG. 1 is an X-ray diffraction chart of the target. From this figure, it was confirmed that hexagonal layered compounds represented by InSmO 3 and In 2 O 3 (ZnO) 3 were generated in the target.
［酸化物半導体薄膜の成膜］
　製造したスパッタリングターゲットをＤＣマグネトロンスパッタリング装置に装着して、スパッタリングし、ガラス基板上に厚みが５０ｎｍである酸化物半導体薄膜を成膜した。スパッタリング中に異常放電は確認されなかった。
　上記スパッタリングは、最初に５×１０－４Ｐａまで系内を減圧にし、アルゴンを９．５ＳＣＣＭで、及び酸素を０．５ＳＣＣＭで流しながら圧力を０．３Ｐａに調整して行った。
　この際、最初に減圧にした圧力を水分の分圧とし、酸素分圧は、アルゴン：酸素を流して圧力を調整したときの酸素の分圧とした。従って、酸素分圧／水の分圧＝（０．３×０．５／（９．５＋０．５））／（５×１０－４）＝３０であった。 [Formation of oxide semiconductor thin film]
The manufactured sputtering target was attached to a DC magnetron sputtering apparatus and sputtered to form an oxide semiconductor thin film having a thickness of 50 nm on a glass substrate. Abnormal discharge was not confirmed during sputtering.
The sputtering was performed by first reducing the pressure in the system to 5 × 10 −4 Pa and adjusting the pressure to 0.3 Pa while flowing argon at 9.5 SCCM and oxygen at 0.5 SCCM.
At this time, the first reduced pressure was the moisture partial pressure, and the oxygen partial pressure was the oxygen partial pressure when the pressure was adjusted by flowing argon: oxygen. Therefore, the partial pressure of oxygen / partial pressure of water = (0.3 × 0.5 / (9.5 + 0.5)) / (5 × 10 −4 ) = 30.
　成膜した薄膜を空気中にて３００℃で１時間加熱処理して安定化させた。得られた酸化物半導体薄膜についてＸ線回折より結晶性をみたところ、ピークは観察されず、非晶質であることを確認した。また、Ｈａｌｌ測定（東洋テクニカ社製：ＲＥＳＩＴＥＳＴ８３００）により、薄膜のキャリヤー密度を測定したところ、キャリヤー密度は、３×１０１７／ｃｍ３であった。
　また、得られた酸化物半導体薄膜の原子比は、ＩＣＰ発光分析で測定したところ、用いたターゲット組成と同一（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．８９、Ｓｍ／（Ｉｎ＋Ｓｍ＋Ｚｎ）＝０．２１）であった。 The formed thin film was stabilized by heat treatment at 300 ° C. for 1 hour in air. When the crystallinity of the obtained oxide semiconductor thin film was observed by X-ray diffraction, no peak was observed, and it was confirmed to be amorphous. Further, the carrier density of the thin film was measured by Hall measurement (manufactured by Toyo Technica Co., Ltd .: REISTEST 8300). As a result, the carrier density was 3 × 10 17 / cm 3 .
The atomic ratio of the obtained oxide semiconductor thin film was the same as the target composition used (In / (In + Zn) = 0.89, Sm / (In + Sm + Zn) = 0.21) as measured by ICP emission analysis. there were.
［半導体特性の評価］
　３００ｎｍ厚みの熱酸化膜付きのハードドープＳｉ基板の熱酸化膜上に、厚さが５０ｎｍの酸化物半導体薄膜を同様にして成膜し、金電極を有するチャンネル長：２００μｍ、チャンネル幅：５００μｍの薄膜トランジスタ素子を作製した。作製した薄膜トランジスタについて、半導体特性評価装置４２００－ＳＣＳ（ケースレーインスツルメント社製）を用いて、その半導体特性を評価したところ、Ｏｎ／Ｏｆｆ値が１０７、電界効果移動度＝１２ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）が１．２Ｖ、Ｓ値が０．６であり、薄膜トランジスタとして十分機能することが分かった。 [Evaluation of semiconductor characteristics]
An oxide semiconductor thin film with a thickness of 50 nm is formed in the same manner on a thermal oxide film of a hard-doped Si substrate with a 300 nm thick thermal oxide film, and has a channel length of 200 μm and a channel width of 500 μm with gold electrodes. A thin film transistor element was produced. The manufactured thin film transistor was evaluated for its semiconductor characteristics using a semiconductor characteristic evaluation apparatus 4200-SCS (manufactured by Keithley Instruments Co., Ltd.). As a result, the On / Off value was 10 7 and the field-effect mobility = 12 cm 2 / V · sec, the threshold voltage (Vth) was 1.2 V, and the S value was 0.6, which proved to function sufficiently as a thin film transistor.
実施例２
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化イッテルビウム粉及び酸化亜鉛粉（重量比で６０：３０：１０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．７８、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．２２））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＹｂＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図２）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．７８、Ｙｂ／（Ｉｎ＋Ｓｍ＋Ｚｎ）＝０．２２であり、キャリヤー密度が３×１０１７／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０７、電界効果移動度＝１０ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．３Ｖ、Ｓ値＝０．７であり、薄膜トランジスタとして十分機能することが分かった。 Example 2
Indium oxide powder, ytterbium oxide powder and zinc oxide powder (weight ratio 60:30:10 (In / (In + Zn) = 0.78, Yb) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Yb+Zn)=0.22)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 2), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.78, Yb / (In + Sm + Zn) = 0.22, and the carrier density was 3 × 10 17 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor properties of the obtained oxide semiconductor thin film are On / Off value = 10 7 , field-effect mobility = 10 cm 2 / V · sec, threshold voltage (Vth) = 1.3 V, S value = 0.7. It was found that it functions sufficiently as a thin film transistor.
実施例３
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化イッテルビウム粉及び酸化亜鉛粉（重量比で４５：３２：２３（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．５３、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．２１））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＹｂＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図３）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．５３、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．２１であり、キャリヤー密度が１×１０１７／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０７、電界効果移動度＝８ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．５Ｖ、Ｓ値＝０．９であり、薄膜トランジスタとして十分機能することが分かった。 Example 3
Indium oxide powder, ytterbium oxide powder and zinc oxide powder (weight ratio 45:32:23 (In / (In + Zn) = 0.53, Yb) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Yb+Zn)=0.21)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 3), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.53, Yb / (In + Yb + Zn) = 0.21, and the carrier density was 1 × 10 17 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor properties of the obtained oxide semiconductor thin film are On / Off value = 10 7 , field effect mobility = 8 cm 2 / V · sec, threshold voltage (Vth) = 1.5 V, S value = 0.9. It was found that it functions sufficiently as a thin film transistor.
実施例４
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化イッテルビウム粉及び酸化亜鉛粉（重量比で３３：４７：２０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．４９、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．３３））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＹｂＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図４）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．４９、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．３３であり、キャリヤー密度が６×１０１６／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０８、電界効果移動度＝７ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．８Ｖ、Ｓ値＝１．２であり、薄膜トランジスタとして十分機能することが分かった。 Example 4
Indium oxide powder, ytterbium oxide powder and zinc oxide powder (weight ratio 33:47:20 (In / (In + Zn) = 0.49, Yb) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Yb+Zn)=0.33)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 4), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.49, Yb / (In + Yb + Zn) = 0.33, and the carrier density was 6 × 10 16 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor characteristics of the obtained oxide semiconductor thin film were On / Off value = 10 8 , field-effect mobility = 7 cm 2 / V · sec, threshold voltage (Vth) = 1.8 V, and S value = 1.2. It was found that it functions sufficiently as a thin film transistor.
実施例５
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化イッテルビウム粉及び酸化亜鉛粉（重量比で２５：３５：４０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．２７、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．２１））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＹｂＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図５）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．２７、Ｙｂ／（Ｉｎ＋Ｙｂ＋Ｚｎ）＝０．２１であり、キャリヤー密度が２×１０１６／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０９、電界効果移動度＝４ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝２．６Ｖ、Ｓ値＝２．８であり、薄膜トランジスタとして十分機能することが分かった。 Example 5
Indium oxide powder, ytterbium oxide powder and zinc oxide powder (weight ratio 25:35:40 (In / (In + Zn) = 0.27, Yb) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Yb+Zn)=0.21)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InYbO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 5), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.27, Yb / (In + Yb + Zn) = 0.21, and the carrier density was 2 × 10 16 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor properties of the obtained oxide semiconductor thin film are On / Off value = 10 9 , field-effect mobility = 4 cm 2 / V · sec, threshold voltage (Vth) = 2.6 V, and S value = 2.8. It was found that it functions sufficiently as a thin film transistor.
実施例６
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ガドリニウム粉及び酸化亜鉛粉（重量比で７０：２６：４（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．９１、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．２１））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＧｄＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図６）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．９１、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．２１であり、キャリヤー密度が５×１０１７／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０６、電界効果移動度＝１５ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．８Ｖ、Ｓ値＝１．５であり、薄膜トランジスタとして十分機能することが分かった。 Example 6
Indium oxide powder, gadolinium oxide powder and zinc oxide powder (70: 26: 4 by weight ratio (In / (In + Zn) = 0.91, Gd) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Gd+Zn)=0.21)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InGdO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 6), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.91, Gd / (In + Gd + Zn) = 0.21, and the carrier density was 5 × 10 17 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor characteristics of the obtained oxide semiconductor thin film are On / Off value = 10 6 , field-effect mobility = 15 cm 2 / V · sec, threshold voltage (Vth) = 1.8 V, and S value = 1.5. It was found that it functions sufficiently as a thin film transistor.
実施例７
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ガドリニウム粉及び酸化亜鉛粉（重量比で５３：２９：１８（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．６３、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．２１））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＧｄＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図７）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．６３、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．２１であり、キャリヤー密度が７×１０１６／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０７、電界効果移動度＝７ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝３．２Ｖ、Ｓ値＝３．２であり、薄膜トランジスタとして十分機能することが分かった。 Example 7
Indium oxide powder, gadolinium oxide powder and zinc oxide powder (in weight ratio 53:29:18 (In / (In + Zn) = 0.63, Gd) instead of raw material indium oxide powder, samarium oxide and zinc oxide powder /(In+Gd+Zn)=0.21)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InGdO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 7), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.63, Gd / (In + Gd + Zn) = 0.21, and the carrier density was 7 × 10 16 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor properties of the obtained oxide semiconductor thin film are On / Off value = 10 7 , field-effect mobility = 7 cm 2 / V · sec, threshold voltage (Vth) = 3.2 V, and S value = 3.2. It was found that it functions sufficiently as a thin film transistor.
実施例８
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ガドリニウム粉及び酸化亜鉛粉（重量比で３５：４５：２０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．５１、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．３３））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＧｄＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図８）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．５１、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．３３であり、キャリヤー密度が９×１０１６／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０７、電界効果移動度＝５ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝２．８Ｖ、Ｓ値＝３．１であり、薄膜トランジスタとして十分機能することが分かった。 Example 8
Indium oxide powder, gadolinium oxide powder and zinc oxide powder (in weight ratio 35:45:20 (In / (In + Zn) = 0.51, Gd) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Gd+Zn)=0.33)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InGdO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 8), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.51, Gd / (In + Gd + Zn) = 0.33, and the carrier density was 9 × 10 16 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor properties of the obtained oxide semiconductor thin film are On / Off value = 10 7 , field-effect mobility = 5 cm 2 / V · sec, threshold voltage (Vth) = 2.8 V, and S value = 3.1. It was found that it functions sufficiently as a thin film transistor.
実施例９
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ガドリニウム粉及び酸化亜鉛粉（重量比で２７：３３：４０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．２８、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．２１））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＧｄＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図９）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．２８、Ｇｄ／（Ｉｎ＋Ｇｄ＋Ｚｎ）＝０．２１であり、キャリヤー密度が２×１０１６／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０８、電界効果移動度＝３ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝２．６Ｖ、Ｓ値＝３．２であり、薄膜トランジスタとして十分機能することが分かった。 Example 9
Indium oxide powder, gadolinium oxide powder and zinc oxide powder (27:33:40 by weight ratio (In / (In + Zn) = 0.28, Gd) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Gd+Zn)=0.21)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InGdO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 9), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.28, Gd / (In + Gd + Zn) = 0.21, and the carrier density was 2 × 10 16 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor characteristics of the obtained oxide semiconductor thin film are On / Off value = 10 8 , field-effect mobility = 3 cm 2 / V · sec, threshold voltage (Vth) = 2.6 V, and S value = 3.2. It was found that it functions sufficiently as a thin film transistor.
実施例１０
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ジスプロシウム粉及び酸化亜鉛粉（重量比で４５：３５：２０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．５７、Ｄｙ／（Ｉｎ＋Ｄｙ＋Ｚｎ）＝０．２５））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＤｙＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図１０）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．５７、Ｄｙ／（Ｉｎ＋Ｄｙ＋Ｚｎ）＝０．２５であり、キャリヤー密度が４×１０１７／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０７、電界効果移動度＝８ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．５Ｖ、Ｓ値＝１．２であり、薄膜トランジスタとして十分機能することが分かった。 Example 10
Indium oxide powder, dysprosium oxide powder and zinc oxide powder (weight ratio 45:35:20 (In / (In + Zn) = 0.57, Dy) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Dy+Zn)=0.25)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InDyO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 10), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.57, Dy / (In + Dy + Zn) = 0.25, and the carrier density was 4 × 10 17 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor characteristics of the obtained oxide semiconductor thin film are On / Off value = 10 7 , field effect mobility = 8 cm 2 / V · sec, threshold voltage (Vth) = 1.5 V, S value = 1.2. It was found that it functions sufficiently as a thin film transistor.
実施例１１
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化エルビウム粉及び酸化亜鉛粉（重量比で４５：３５：２０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．５７、Ｅｒ／（Ｉｎ＋Ｅｒ＋Ｚｎ）＝０．２４））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＥｒＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図１１）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．５７、Ｅｒ／（Ｉｎ＋Ｅｒ＋Ｚｎ）＝０．２４であり、キャリヤー密度が１×１０１７／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０８、電界効果移動度＝１１ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．６Ｖ、Ｓ値＝１．２であり、薄膜トランジスタとして十分機能することが分かった。 Example 11
Indium oxide powder, erbium oxide powder and zinc oxide powder (weight ratio 45:35:20 (In / (In + Zn) = 0.57, Er) instead of the raw material powders of indium oxide powder, samarium oxide and zinc oxide powder /(In+Er+Zn)=0.24)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that a hexagonal layered compound represented by InErO 3 and In 2 O 3 (ZnO) 3 was generated in the obtained target (FIG. 11), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.57, Er / (In + Er + Zn) = 0.24, and the carrier density was 1 × 10 17 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor characteristics of the obtained oxide semiconductor thin film are On / Off value = 10 8 , field effect mobility = 11 cm 2 / V · sec, threshold voltage (Vth) = 1.6 V, and S value = 1.2. It was found that it functions sufficiently as a thin film transistor.
実施例１２
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ランタン粉及び酸化亜鉛粉（重量比で７０：２５：５（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．８９、Ｌａ／（Ｉｎ＋Ｌａ＋Ｚｎ）＝０．２１））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎＬａＯ３及びＩｎ２Ｏ３（ＺｎＯ）３で表される六方晶層状化合物が生成していることが確認でき（図１２）、得られた酸化物半導体薄膜は、原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．９０、Ｌａ／（Ｉｎ＋Ｌａ＋Ｚｎ）＝０．２２であり、キャリヤー密度が２．４×１０１７／ｃｍ３であることを確認した。また、スパッタリング中に異常放電は確認されなかった。
　得られた酸化物半導体薄膜の半導体特性は、Ｏｎ／Ｏｆｆ値＝１０８、電界効果移動度＝１２ｃｍ２／Ｖ・ｓｅｃ、閾値電圧（Ｖｔｈ）＝１．５Ｖ、Ｓ値＝１．３であり、薄膜トランジスタとして十分機能することが分かった。 Example 12
Indium oxide powder, lanthanum oxide powder and zinc oxide powder (weight ratio 70: 25: 5 (In / (In + Zn) = 0.89, La) instead of the raw material indium oxide powder, samarium oxide and zinc oxide powder /(In+La+Zn)=0.21)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, it was confirmed that hexagonal layered compounds represented by InLaO 3 and In 2 O 3 (ZnO) 3 were generated in the obtained target (FIG. 12), and the obtained oxide semiconductor thin film was It was confirmed that the atomic ratio was In / (In + Zn) = 0.90, La / (In + La + Zn) = 0.22, and the carrier density was 2.4 × 10 17 / cm 3 . Also, no abnormal discharge was observed during sputtering.
The semiconductor properties of the obtained oxide semiconductor thin film are On / Off value = 10 8 , field effect mobility = 12 cm 2 / V · sec, threshold voltage (Vth) = 1.5 V, S value = 1.3. It was found that it functions sufficiently as a thin film transistor.
比較例１
　原料粉である酸化インジウム粉、酸化サマリウム及び酸化亜鉛粉の代わりに、酸化インジウム粉、酸化ランタン粉及び酸化亜鉛粉（重量比で８５：５：１０（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．８３、Ｌａ／（Ｉｎ＋Ｌａ＋Ｚｎ）＝０．０４））を用いた他は実施例１と同様にしてスパッタリングターゲットを作製及び評価し、酸化物半導体薄膜を成膜及び評価した。
　その結果、得られたターゲット中にＩｎ２Ｏ３及びＩｎ２Ｏ３（ＺｎＯ）３の生成は確認できたが、ＩｎＬａＯ３が生成していることは確認できなった（図１３）。これは、Ｌａの添加量が少ない場合には、Ｉｎ２Ｏ３のインジウムサイト又はＩｎ２Ｏ３（ＺｎＯ）３のインジウムサイトにＬａが固溶置換していると考えられる。 Comparative Example 1
Indium oxide powder, lanthanum oxide powder and zinc oxide powder (weight ratio 85: 5: 10 (In / (In + Zn) = 0.83, La) instead of the raw material indium oxide powder, samarium oxide and zinc oxide powder /(In+La+Zn)=0.04)) was used, and a sputtering target was prepared and evaluated in the same manner as in Example 1, and an oxide semiconductor thin film was formed and evaluated.
As a result, generation of In 2 O 3 and In 2 O 3 (ZnO) 3 was confirmed in the obtained target, but it was not confirmed that InLaO 3 was generated (FIG. 13). This is because if the added amount of La is small, La is considered to be a solid solution an indium site substituted or In 2 O 3 (ZnO) 3 of indium sites of In 2 O 3.
　また、得られた酸化物半導体薄膜の原子比がＩｎ／（Ｉｎ＋Ｚｎ）＝０．８３、Ｌａ／（Ｉｎ＋Ｌａ＋Ｚｎ）＝０．０４であり、キャリヤー密度が２×１０２０／ｃｍ３であることを確認した。
　得られた酸化物半導体薄膜は、キャリヤー密度が２×１０２０／ｃｍ３であることから、導電性の薄膜であり、半導体特性を評価することはできなかった。 In addition, it is confirmed that the atomic ratio of the obtained oxide semiconductor thin film is In / (In + Zn) = 0.83, La / (In + La + Zn) = 0.04, and the carrier density is 2 × 10 20 / cm 3. did.
Since the obtained oxide semiconductor thin film had a carrier density of 2 × 10 20 / cm 3 , it was a conductive thin film, and its semiconductor characteristics could not be evaluated.
比較例２
　原料粉として、原子比が（Ｉｎ／（Ｉｎ＋Ｚｎ）＝０．８０、Ｓｍ／（Ｉｎ＋Ｚｎ＋Ｓｍ）＝０．１５）である酸化インジウム粉、酸化ランタン粉及び酸化亜鉛粉を用いた他は実施例１と同様にして上記原子比のスパッタリングターゲットを作製した。酸素を用いずアルゴンのみの気流下で成膜を行った他は実施例１と同様にして酸化物半導体薄膜を成膜した。得られた透明導電膜の比抵抗は３５００μΩｃｍであった。 Comparative Example 2
Example 1 except that indium oxide powder, lanthanum oxide powder and zinc oxide powder having an atomic ratio of (In / (In + Zn) = 0.80, Sm / (In + Zn + Sm) = 0.15) were used as the raw material powder. Similarly, a sputtering target having the above atomic ratio was produced. An oxide semiconductor thin film was formed in the same manner as in Example 1 except that the film was formed in an air stream containing only argon without using oxygen. The specific resistance of the obtained transparent conductive film was 3500 μΩcm.
　本発明のターゲットは、液晶表示装置（ＬＣＤ）用透明導電膜、エレクトロルミネッセンス（ＥＬ）表示素子用透明導電膜、太陽電池用透明導電膜等、種々の用途の透明導電膜、酸化物半導体薄膜をスパッタリング法により得るためのターゲットとして好適である。例えば、有機ＥＬ素子の電極や、半透過・半反射ＬＣＤ用の透明導電膜、液晶駆動用酸化物半導体膜、有機ＥＬ素子駆動用酸化物半導体薄膜を得ることができる。
　この明細書に記載の文献の内容を全てここに援用する。 The target of the present invention is a transparent conductive film for various uses, such as a transparent conductive film for a liquid crystal display (LCD), a transparent conductive film for an electroluminescence (EL) display element, a transparent conductive film for a solar cell, and an oxide semiconductor thin film. It is suitable as a target for obtaining by a sputtering method. For example, an electrode of an organic EL element, a transparent conductive film for a semi-transmissive / semi-reflective LCD, an oxide semiconductor film for driving a liquid crystal, and an oxide semiconductor thin film for driving an organic EL element can be obtained.
The entire contents of the documents described in this specification are incorporated herein by reference.

Claims (11)

  1. 　Ｉｎ２Ｏ３（ＺｎＯ）ｍ（式中、ｍは２～２０の整数である）で表される六方晶層状化合物、及びＩｎＬｎＯ３（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）で表される化合物を含み、原子比が、０．２＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９７、０．０３＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．８、及び０．２＜（Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．５である焼結体。 A hexagonal layered compound represented by In 2 O 3 (ZnO) m (wherein m is an integer of 2 to 20), and InLnO 3 (Ln is a trivalent lanthanoid element excluding Pr and Pm). The atomic ratio is 0.2 <In / (In + Zn) <0.97, 0.03 <Zn / (In + Zn) <0.8, and 0.2 <(Ln / (In + Zn + Ln) < Sintered body which is 0.5.
  2. 　全カチオン金属元素に対するＩｎの含有量［Ｉｎ／（全金属カチオン）：原子比］が、全金属カチオン元素に対するＬｎの含有量［Ｌｎ／（全金属カチオン）：原子比］より多い請求項１に記載の焼結体。 The In content [In / (total metal cation): atomic ratio] relative to the total cationic metal element is greater than the content [Ln / (total metal cation): atomic ratio] of Ln relative to the total metallic cation element. The sintered body described.
  3. 　バルク抵抗が５ｍΩｃｍ未満である請求項１又は２に記載の焼結体。 The sintered body according to claim 1 or 2, wherein the bulk resistance is less than 5 mΩcm.
  4. 　請求項１～３のいずれかに記載の焼結体からなるスパッタリングターゲット。 A sputtering target comprising the sintered body according to any one of claims 1 to 3.
  5. 　Ｉｎ、Ｚｎ及びＬｎ（ＬｎはＰｒ及びＰｍを除く３価のランタノイド元素）を含み、
    　原子比が、０．２＜Ｉｎ／（Ｉｎ＋Ｚｎ）＜０．９７、０．０３＜Ｚｎ／（Ｉｎ＋Ｚｎ）＜０．８、及び０．２＜Ｌｎ／（Ｉｎ＋Ｚｎ＋Ｌｎ）＜０．５である酸化物半導体薄膜。     In, Zn and Ln (Ln is a trivalent lanthanoid element excluding Pr and Pm),
    Oxides having atomic ratios of 0.2 <In / (In + Zn) <0.97, 0.03 <Zn / (In + Zn) <0.8, and 0.2 <Ln / (In + Zn + Ln) <0.5 Semiconductor thin film.
  6. 　キャリヤー密度が１０１８／ｃｍ３未満である請求項５に記載の酸化物半導体薄膜。 The oxide semiconductor thin film according to claim 5, wherein the carrier density is less than 10 18 / cm 3 .
  7. 　スパッタ圧力を０．１～２Ｐａとし、酸素分圧を前記スパッタ圧力の２～２０％として、請求項４に記載のスパッタリングターゲットをスパッタリングする酸化物半導体薄膜の製造方法。 The method for producing an oxide semiconductor thin film by sputtering a sputtering target according to claim 4, wherein the sputtering pressure is 0.1 to 2 Pa and the oxygen partial pressure is 2 to 20% of the sputtering pressure.
  8. 　前記スパッタリングを、下記式を満たす雰囲気中で行う請求項７に記載の酸化物半導体薄膜の製造方法。
    　　１０＜（酸素分圧／水の分圧）＜２００     The manufacturing method of the oxide semiconductor thin film of Claim 7 which performs the said sputtering in the atmosphere which satisfy | fills following formula.
    10 <(partial pressure of oxygen / partial pressure of water) <200
  9. 　請求項５又は６に記載の酸化物半導体薄膜を用いる薄膜トランジスタ。 A thin film transistor using the oxide semiconductor thin film according to claim 5 or 6.
  10. 　チャンネルエッチ型である請求項９に記載の薄膜トランジスタ。 The thin film transistor according to claim 9, which is a channel etch type.
  11. 　エッチストッパー型である請求項９に記載の薄膜トランジスタ。 The thin film transistor according to claim 9, which is an etch stopper type.
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