Gate dielectric based on oxynitride grown in N.sub.2 O and annealed in NO

A method for in situ rapid thermal growth of a nitrided SiO.sub.2 layer on a silicon substrate, comprising:

• placing the silicon substrate in a rapid thermal process chamber, introducing a first gas into the process chambers, said first gas comprising N.sub.2 O, heating the surface of the silicon substrate to a first reaction temperature to cause growth of a layer of SiO.sub.2 on the surface, said layer of SiO.sub.2 including nitrogen, and after a first reaction time, cooling the silicon substrate;
• removing the first gas from the process chamber, introducing a second gas into the process chamber, said second gas comprising NO, heating the layer of SiO.sub.2 to a second reaction temperature to cause formation of silicon to nitrogen bonds in an interfacial region between the layer of SiO.sub.2 and the silicon substrate, and after a second reaction time, cooling the silicon substrate;
• and
• removing the second gas from the reaction chamber, filing the process chamber with an inert gas, and heating the layer to anneal the layer of SiO.sub.2 and the interfacial region.