Tantalum and niobium compounds and their use for chemical vapour deposition (CVD)

1. A compound of the formula (I)

wherein

M stands for Ta or Nb,

R 1 and R 2 mutually independently denote optionally substituted C 1 to C 12 alkyl, C 5 to C 12 cycloalkyl or C 6 to C 10 aryl radicals, 1-alkenyl, 2-alkenyl, 3-alkenyl or triorganosilyl radicals —SiR 3 , or amino radicals NR 2 wherein R stands for a C 1 to C 4 alkyl radical,

R 3 denotes an optionally substituted C 1 to C 8 alkyl, C 5 to C 10 cycloalkyl, C 6 to C 14 aryl radical, or SiR 3 , or NR 2 wherein R has the aforementioned meaning,

R 4 denotes (a) halogen selected from the group consisting of Cl, Br, and I,

(b) NH—R 5 where R 5 =optionally substituted C 1 to C 8 alkyl, C 5 to C 10 cycloalkyl or C 6 to C 10 aryl radical,

(c) O—R 6 where R 6 =optionally substituted C 1 to C 11 alkyl, C 5 to C 10 cycloalkyl or C 6 to C 10 aryl radical,

(d) —SiR 3 ,

(e) BH 4 ,

(f) an optionally substituted allyl radical,

(g) an indenyl radical,

(h) optionally substituted benzyl radical,

(i) an optionally substituted cyclopentadienyl radical,

(j) —NR—NR′R″ (hydrazido(−1), wherein R, R′ and R″ mutually independently have the aforementioned meaning of R,

(k) CH 2 SiMe 3 ,

(l) pseudohalide, or

(m) silylamide —N(SiMe 3 ) 2 ,

R 7 and R 8 mutually independently denote H, optionally substituted C 1 to C 12 alkyl, C 5 to C 12 cycloalkyl or C 6 to C 10 aryl radicals.

2. The compound according to claim 1 , which corresponds to formula II,

wherein

M stands for Ta or Nb,

R 1 and R 2 denote identical C 1 to C 5 alkyl or C 5 to C 6 cycloalkyl radicals,

R 3 denotes a C 1 to C 5 alkyl, C 5 to C 6 cycloalkyl or optionally substituted phenyl radical,

R 4 denotes

a ) halogen selected from the group consisting of Cl, Br, and I,

b) a radical NH—R 5 where R 5 =C 1 to C 5 alkyl, C 5 to C 6 cycloalkyl or optionally substituted C 6 to C 10 aryl radical,

e) BH 4 ,

f) an optionally substituted allyl radical,

(h) optionally substituted benzyl radical,

(i) an optionally substituted cyclopentadienyl radical or an oxyalkyl radical.

3. The compound according to claim 1 corresponding to the formula (III),

wherein

R 3 and R 4 mutually independently denote an identical or different radical from the group of C 1 to C 5 alkyl radicals, or C 6 to C 10 aryl radicals optionally substituted by one to three C 1 to C 5 alkyl groups.

4. The compound according to claim 2 selected from the group consisting of:

5. The compound according to claim 2 corresponding to the formula (XI),

wherein R 6 denotes an optionally substituted C 1 to C 12 alkyl radical.

6. The compound according to claim 5 corresponding to the structure (XII):

7. The compound according to claim 2 corresponding to the structure (XIII),

wherein

R 9 denotes a radical of an enolate having the formula (XIV),

in which

R 10 denotes a C 1 to C 4 alkyl radical and R 11 is the same as R 10 or mutually independently denotes OR 10 .

8. A tantalum-containing coating which comprise the compound of claim 1 .

9. A substrate which comprises the tantalum-containing coating as claimed in claim 8 .

10. A niobium-containing coating which comprises the compound of claim 1 .

11. A substrate which comprises the niobium-containing coating as claimed in claim 10 .

12. A TaN-containing coating which comprises the compound of claim 1 .

13. A NbN-containing coating which comprises the compound of claim 1 .