Method of forming nitrided oxide in a hot wall single wafer furnace
AssigneeCypress Semiconductor Corporation
InventorsKrishnaswamy Ramkumar, Sundar Narayanan
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Abstract
A method of nitriding a gate oxide layer by annealing a preformed oxide layer with nitric oxide (NO) gas in a hot wall, single wafer furnace is provided. The nitridation process can be carried out rapidly (i.e., at nitridation times of 30 seconds to 2 minutes) while providing acceptable levels of nitridation (i.e., up to 6 at. %) and desirable nitrogen/depth profiles. The nitrided gate oxide layer can optionally be reoxidized in a second oxidation step after the nitridation step. A gate electrode layer (e.g., boron doped polysilicon) can then be deposited on top of the nitrided gate oxide layer or on top of the reoxidized and nitrided gate oxide layer.
Claims21
A method of nitriding a gate oxide layer on a semiconductor substrate comprising:
- nitriding the gate oxide layer in the presence of nitric oxide (NO) gas;
- wherein the nitriding step is conducted in a single wafer, hot wall furnace.
A semiconductor device comprising:
- a semiconductor substrate layer;
- a nitrided gate oxide layer disposed on the substrate layer to form a gate oxide/substrate interface;
- and
- a boron doped gate electrode layer disposed on the nitrided gate oxide layer;
- wherein the boron dopant in the gate electrode layer has been activated, and wherein the boron concentration in the semiconductor substrate layer at a distance of 5 nm or more from the gate oxide/substrate interface is no more than 1 percent of the average boron concentration in the gate electrode layer.
Dependencies are inferred from the claim text.