Semiconductor device and method for manufacturing the same
View Patent ↗It is made possible to provide a method for manufacturing a semiconductor device that has a high-quality insulating film in which defects are not easily formed, and experiences less leakage current. A method for manufacturing a semiconductor device, includes: forming an amorphous silicon layer on an insulating layer; introducing oxygen into the amorphous silicon layer; and forming a silicon oxynitride layer by nitriding the amorphous silicon layer having oxygen introduced thereinto.
1. A method for manufacturing a semiconductor device, comprising:
forming a first silicon oxide layer on a silicon substrate;
forming a first silicon oxynitride layer by nitriding the first silicon oxide layer;
forming an amorphous silicon layer on the first silicon oxynitride layer;
introducing oxygen into the amorphous silicon layer;
forming a second silicon oxynitride layer by nitriding the amorphous silicon layer having oxygen introduced thereinto; and
forming a second silicon oxide layer on the second silicon oxynitride layer, thereby forming a three-layer structure including the first silicon oxynitride layer having an average nitrogen concentration higher than 0 atomic % but not higher than 10 atomic %, the second silicon oxynitride layer having an average oxygen concentration in the range of 10 atomic % to 30 atomic %, and the second silicon oxide layer.
2. The method according to claim 1 , further comprising
nitriding a surface of the first silicon oxide layer before forming the amorphous silicon layer on the first silicon oxide layer.
3. The method according to claim 2 , further comprising
introducing Ge into the first silicon oxide layer before nitriding the surface of the first silicon oxide layer.
4. The method according to claim 1 , further comprising
oxidizing the second silicon oxynitride layer before forming the second silicon oxide layer.
5. The method according to claim 1 , further comprising
performing oxidation to the three-layer structure in an oxidizing atmosphere at a temperature between 900° C. and 950° C. for ten minutes or longer, after forming the three-layer structure including the first silicon oxynitride layer, the second silicon oxynitride layer, and the second silicon oxide layer.
6. The method according to claim 1 , wherein the introducing oxygen into the amorphous silicon layer includes introducing oxygen into the amorphous silicon layer in an atmosphere of an oxidizing gas at a temperature between 700° C. and 800° C. for ten seconds or shorter.
7. The method according to claim 6 , wherein the oxidizing gas contains O 2 , NO, N 2 O, O 3 , O radicals, or O plasma.
8. The method according to claim 1 , wherein the forming the second silicon oxynitride layer by nitriding the amorphous silicon layer includes nitriding the amorphous silicon layer at a temperature between 600° C. and 750° C.
9. A semiconductor device comprising an insulating film, the insulating film including:
a first silicon oxynitride layer formed on a silicon substrate and having average nitrogen concentration higher than 0 atomic % but not higher than 10 atomic %;
a second silicon oxynitride layer formed on the first silicon oxynitride layer and having average oxygen concentration in the range of 10 atomic % to 30 atomic %; and
a silicon oxide layer formed on the second silicon oxynitride layer.
10. The device according to claim 9 , wherein the second silicon oxynitride layer has average nitrogen concentration in the range of 20 atomic % to 47 atomic %.
11. The device according to claim 9 , wherein the first silicon oxynitride layer contains Ge.