Method and apparatus for making nitrided gate oxide

A method for forming a semiconductor device having a nitrided gate oxide, the method comprising:

• flowing an N2O gas into an external torch set at a temperature of at least about 850° C.;
• decomposing the N2O gas in the external torch to provide to provide a Hi decomposed gas including N2O, NO, and O2, the NO being of sufficient amount to perform a nitrogen incorporation step within a furnace;
• and
• flowing the decomposed gas into the furnace including a substrate to form a nitrided gate oxide having a nitrogen concentration of at least about 1% atomic weight and a thickness of about 50 angstroms or less.

A method for forming a semiconductor device P type metal oxide semiconductor field effect transistor (PMOSFET) on a silicon substrate, the method comprising:

• forming an oxide layer a thickness of less than 50 angstroms over the substrate;
• flowing an N2O gas into an external torch set at a temperature of at between about 850° C. and about 1000° C. to decompose the N2O gas in the external torch to provide a decomposed gas including N2O, NO, and O2;
• flowing the decomposed gas including N2O, NO, and O2 into a furnace wherein the substrate with the oxide layer is provided;
• annealing the substrate within the furnace in an environment of the decomposed gas to incorporate nitrogen from N2O and NO into the gate oxide layer overlying the substrate to form a nitrided gate oxide having a nitrogen concentration of at least about 1% atomic weight and a thickness of more than about 50 angstroms, a temperature within the furnace being maintained at between 700° C.-800° C. during the anneal step;
• and
• forming a polysilicon layer overlying the nitrided gate oxide, the polysilicon layer having a concentration of boron,
• wherein the nitrogen concentration in the nitrided gate oxide reduces diffusion of boron from the polysilicon layer into the substrate.