Method of fabricating semiconductor by nitrogen doping of silicon film
A method of fabricating a semiconductor uses chemical vapor deposition, or plasma-enhanced chemical vapor deposition, to deposit an amorphous silicon film on an exposed surface of a substrate, such as ASIC wafer. The amorphous silicon film is doped with nitrogen to reduce the conductivity of the film and/or to augment the breakdown voltage of the film. Nitrogen gas, N 2 , is activated or ionized in a reactor before it is deposited on the substrate.
1. A method of fabricating a component of a semiconductor structure by chemical vapor deposition of an amorphous silicon film on an exposed surface of a substrate, CHARACTERISED IN THAT the amorphous silicon film is doped with nitrogen; and
parameters of the vapor deposition being varied to control the electrical properties of the nitrogen doped silicon film to have a high resistivity and to prevent surface electrical breakdown of the semiconductor structure.
2. A method as claimed in claim 1 , CHARACTERISED IN THAT the nitrogen is N2.
3. A method as claimed in claim 2 , CHARACTERISED IN THAT the N2 is flowed at 650 to 750 sccm.
4. A method as claimed in claim 2 , CHARACTERISED IN THAT the nitrogen is activated prior to deposition.
5. A method as claimed in claim 4 , CHARACTERISED IN THAT the nitrogen is activated by radio-frequency energy.
6. A method as claimed in claim 5 , CHARACTERISED IN THAT the radio-frequency energy is from 800 to 1200 Watts.
7. A method as claimed in claim 4 , CHARACTERISED IN THAT the nitrogen is activated by microwave energy.
8. A method as claimed in claim 4 , CHARACTERISED IN THAT the nitrogen is activated by laser.
9. A method as claimed in claim 4 , CHARACTERISED IN THAT the nitrogen is activated by ultraviolet light.
10. A method as claimed in claim 5 , CHARACTERISED IN THAT the silicon film is doped with nitrogen in a vacuum chamber.
11. A method as claimed in claim 10 , CHARACTERISED IN THAT an inert gas and a silicon-based gas are present in the vacuum chamber.
12. A method as claimed in claim 6 , CHARACTERISED IN THAT the nitrogen is activated by ionization in a plasma-enhanced chemical vapor deposition (PECVD) reactor.
13. A method as claimed in claim 1 , CHARACTERISED IN THAT the substrate is an application-specific integrated circuit (ASIC) wafer.
14. A method as claimed in claim 1 CHARACTERISED IN THAT the film exhibits reduced conductivity after doping with nitrogen.
15. A method as claimed in claim 1 CHARACTERISED IN THAT the film has a higher breakdown voltage after doping with nitrogen.