Method for forming a uniform distribution of nitrogen in silicon oxynitride gate dielectric
View Patent ↗Methods for preparing a silicon oxynitride layer where the silicon oxynitride layer is deposited atop a substrate and have a low concentration of nitrogen at the interface of the silicon oxynitride layer and the substrate. The silicon oxynitride layer is formed by pulsing at least one interface precursor onto a substrate, where said substrate chemisorbs a portion of said at least one interface precursor to form a monolayer of said at least one interface precursor; and pulsing a nitrogen-containing precursor onto said substrate containing said monolayer of interface precursor, where said monolayer of said at least one interface precursor chemisorbs a portion of said nitrogen-containing precursor to form a monolayer of said nitrogen-containing precursor. The interface precursor includes oxygen-containing or silicon-containing precursor gasses.
1. A method of forming an insulating film comprising:
a) pulsing a first precursor atop a substrate to provide an OH terminated substrate;
b) performing a first purge;
c) pulsing a Si-containing precursor onto said OH terminated surface so that said OH terminated substrate chemisorbs a portion of said Si-containing precursor to form a Si-monolayer;
d) performing a second purge; and
e) pulsing a N-containing precursor onto said Si-monolayer so that said Si-monolayer chemisorbs a portion of said N-containing precursor to form a N-monolayer, wherein as SiO x N y layer is formed by steps a-e at an interface between the substrate and a gate dielectric, the SiO x N y having a controlled N concentration.
2. The method of claim 1 further comprising the steps of:
f) pulsing an other Si-containing precursor or a Hf-containing precursor to form an other Si-monolayer or a Hf-monolayer; and
g) pulsing an O-containing precursor or an other N-containing precursor to form an O-monolayer or other N-monolayer.
3. The method of claim 2 , where step f) and step g) are performed (n) times, where (n) is a whole number equal to or greater than 1 and less than 50.
4. The method of claim 1 where said providing said OH terminated surface comprises pulsing an O-containing precursor atop a substrate, oxidizing said substrate in an oxidizing ambient, or wet cleaning said substrate with an aqueous solution containing oxidizers.
5. The method of claim 1 , where step b) and c) further comprises purging an O-containing precursor, where said Si-monolayer chemisorbs a portion of said O-containing precursor to form an O-monolayer; and pulsing an other Si-containing precursor, where said O-monolayer chemisorbs a portion of said other Si-containing precursor.
6. The method of claim 1 , where said N-containing precursor comprises NH 3 , N 2 H 4 , or plasma forming N* radicals.
7. The method of claim 1 , where said Si-containing precursor comprises Si-tetrachloride, di-chlorosilane, mono-chlorosilane, or combinations thereof.
8. The method of claim 4 , where said O-containing precursor comprises H 2 O, H 2 O 2 , O 2 , O 3 , or O* radicals.
9. The method of claim 2 , where said Hf-containing precursor comprises HfCl 4 , Hf(OC 2 H 5 ) 4 , or Hf(OC 4 H 9 ) 4 .
10. A method for forming a composite gate dielectric comprising:
providing a substrate;
forming a first dielectric layer atop the substrate; and
forming a second dielectric layer atop said first dielectric layer, where said second dielectric layer is formed by pulsing an O-containing precursor atop said first dielectric layer to form an O-monolayer, performing a first purge, pulsing a Si-containing precursor atop said O-monolayer to form a Si-monolayer, performing a first purge, and pulsing a N-containing precursor atop said Si-monolayer to form a N-monolayer, where said pulsing said O-containing precursor, said pulsing said Si-containing precursor, and said pulsing said N-containing precursor is performed (n) times, where (n) is a whole number equal to or greater than 1, thereby forming a SiO x N y layer having a controller N concentration at an interface between the substrate and the gate dielectric.
11. The method of claim 10 , where said first dielectric layer comprises SiO 2 , or silicon oxynitride.
12. The method of claim 10 , where said first dielectric layer has a thickness of about 2 to about 6 nm.
13. The method of claim 10 , where said second dielectric layer has a thickness of about 1 to about 2 nm.
14. The method of claim 10 , where said second dielectric layer is comprised of silicon oxynitride.
15. The method of claim 10 , further comprising forming a photoresist layer atop a portion of said first gate dielectric; where said second dielectric layer is formed atop said first dielectric layer and atop said photoresist layer.
16. The method of claim 10 , further comprising forming a patterned photoresist layer atop a portion of said first gate dielectric, where a remaining portion of said first gate dielectric is exposed; etching said remaining portion of said first gate dielectric exposing said substrate; stripping said patterned photoresist layer; and forming said second dielectric layer atop said first dielectric layer and atop said substrate.
17. The method of claim 10 , where said first dielectric layer includes a top layer of HfSiON.
18. A semiconductor device comprising:
a silicon oxynitride layer atop a substrate where said silicon oxynitride layer comprises a N:O concentration ratio from about 0 to about 0.50 at an interface between said silicon oxynitride layer and said substrate, where said silicon oxynitride layer includes Cl on the order of about 1 atomic percent.
19. The semiconductor device of claim 18 , where said silicon oxynitride layer comprises a N:O concentration ratio from about 0.05 to 10 about at a surface opposite said interface between said silicon oxynitride layer and said substrate.
20. The semiconductor device of claim 18 where said silicon oxynitride layer further comprises Hf, where the concentration of Hf is less then 15 atomic %.