Liquid double alkoxide of niobium or tantalum and alkaline earth metal, production method thereof, and production method of complex metal oxide dielectric using it

A novel compound shown by M[N(OC

2H

5)

5(OC

2H

4OCH

3)]

2, wherein M represents Sr or Ba, N represents Nb or Ta, which is a liquid at room temperature, is hard to be thermally dissociated, and has a vapor pressure of about 0.2 Torr at 190° C. The compound is produced by reacting 2 moles of N(OC

2H

5)

5 and from 1 to 1.1 moles of M(OC

2H

4OCH

3)

2 and then recovering the product by distillation. By using the compounds as raw materials for a CVD method, an SrBi

2Ta

2O

9 thin film or a (Sr

0.75Ba

0.25)Nb

2O

6 thin film for semiconductor devices can be produced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the measurement result of Sr[Ta(OC

2H

5)

5(OC

2H

4OCH

3)]

2 by

1H-NMR,

FIG. 2 is a graph showing the measurement result of Sr[Ta(OC

2H

5)

5(OC

2H

4OCH

3)]

2 by FT-IR,

FIG. 3 is a graph showing the measurement result of Sr[Ta(OC

2H

5)

5(OC

2H

4OCH

3)]

2 by TG-DTA, and

FIG. 4 is a supposed view of the molecular structure of Sr[Ta(OC

2H

5)

5(OC

2H

4OCH

3)]

2.

1. A compound represented by the following formula I:

M[N(OC

2H

5)

5(OC

2H

4OR)]

2  I

wherein M represents Sr or Ba, N represents Nb or Ta, and R represents an alkyl group having from 1 to 4 carbon atoms.

2. The compound according to claim 1, wherein R is CH

3.

3. A method of producing the compound as claimed in claim 1, which comprises reacting N(OC

2H

5)

5 and M(OC

2H

4OR)

2.

4. A method of producing the compound as claimed in claim 2, which comprises reacting N(OC

2H

5)

5 and M(OC

2H

4OCH

3)

2.

5. A method of producing the compound as claimed in claim 1, which comprises reacting N(OC

2H

5)

5 and M(OC

2H

4OR)

2 and then recovering the product by distillation.

6. A method of producing the compound as claimed in claim 2, which comprises reacting N(OC

2H

5)

5 and M(OC

2H

4OCH

3)

2 and then recovering the product by distillation.

7. A method of producing a dielectric thin film comprising (Sr

pBa

q)Nb

2O

6, wherein p+q=1, by chemical vapor deposition, which comprises the steps of:

8. A method of producing a dielectric thin film comprising (Sr

pBa

q)Nb

2O

6, wherein p+q=1, by chemical vapor deposition, which comprises the steps of:

9. A method of producing a bismuth layered ferroelectric thin film comprising SrBi

2(Ta

xNb

y)

2O

9, wherein x+y=1, by chemical vapor deposition, which comprises the steps of:

10. A method of producing a bismuth layered ferroelectric thin film comprising SrBi

2(Ta

xNb

y)

2O

9, wherein x+y=1, by chemical vapor deposition, which comprises the steps of:

11. A method of producing a thin film comprising the steps of:

 M[N(OC

2H

5)

5(OC

2H

4OR)]

2,

12. A method of producing a thin film, as in claim 11 wherein:

13. A method of producing a thin film, as in claim 11 wherein:

14. A method of producing a thin film, as in claim 11 wherein: