Titanium silicon nitride deposition
Titanium silicon nitride (TiSiN) films are formed in a cyclic chemical vapor deposition process. In some embodiments, the TiSiN films are formed in a batch reactor using TiCl 4 , NH 3 and SiH 4 as precursors. Substrates are provided in a deposition chamber of the batch reactor. In each deposition cycle, a TiN layer is formed on the substrates by flowing TiCl 4 into the deposition chamber simultaneously with NH 3 . The deposition chamber is subsequently flushed with NH 3 . to prepare the TiN layer for silicon incorporation. SiH 4 is subsequently flowed into the deposition chamber. Silicon from the SiH 4 is incorporated into the TiN layers to form TiSiN. Exposing the TiN layers to NH 3 before the silicon precursor has been found to facilitate efficient silicon incorporation into the TiN layers to form TiSiN.
1. A method for forming a titanium silicon nitride film, comprising:
providing a plurality of semiconductor substrates in a deposition chamber of a batch furnace, wherein the deposition chamber can accommodate 25 or more substrates;
depositing titanium silicon nitride on the substrates by performing a plurality of deposition cycles, each cycle comprising the following steps:
A. flowing TiCl 4 into the chamber while simultaneously flowing NH 3 into the chamber, the NH 3 flowing into the chamber at a first flow rate;
B. stopping the flow of TiCl 4 ;
C. flowing NH 3 into the chamber at a second flow rate higher than the first flow rate; and
D. flowing a silicon precursor into the chamber.
2. The method of claim 1 , wherein the second flow rate is at least about two times the first flow rate.
3. A method for forming a titanium silicon nitride film, comprising:
providing a plurality of semiconductor substrates in a deposition chamber of a batch furnace, wherein the deposition chamber can accommodate 25 or more substrates;
depositing titanium silicon nitride on the substrates by performing a plurality of deposition cycles, each cycle comprising the following steps:
A. flowing TiCl 4 into the chamber while simultaneously flowing NH 3 into the chamber, the NH 3 flowing into the chamber at a first flow rate;
B. stopping the flow of TiCl 4 ;
C. flowing NH 3 into the chamber at a second flow rate higher than the first flow rate; and
D. flowing a silicon precursor into the chamber; and
further comprising:
providing a desired resistivity for the titanium silicon nitride; and
selecting a ratio of the step A to the step D based upon the desired resistivity.
4. The method of claim 1 , wherein steps A, B, and C are repeated one or more times before performing step D.
5. The method of claim 1 , wherein step A comprises thermally decomposing the TiCl 4 and the NH 3 on the semiconductor substrates.
6. The method of claim 1 , wherein depositing titanium silicon nitride is performed at a deposition temperature of about 400° C. or more.
7. The method of claim 6 , wherein the deposition temperature is about 500° C. or more.
8. The method of claim 1 , wherein flowing NH 3 into the chamber at the first flow rate while simultaneously flowing TiCl 4 into the chamber deposits a titanium nitride layer having a thickness of about 2 Å or more per cycle.
9. The method of claim 1 , further comprising purging the chamber with inert gas after each of the steps B, C, and D.