| 摘要 |
PURPOSE: A fabrication method of a gate of semiconductor devices is provided to efficiently increase a nitrogen content of a silicon nitride by forming a layered gate oxide using multi-step thermal treatment under an NH3 gas condition. CONSTITUTION: A silicon oxide(13) for a gate is formed on a substrate(11) formed with field oxides(12) and a layered gate oxide is formed by subsequently depositing a first silicon nitride(14) on the silicon oxide(13). After performing a first thermal treatment so as to increase a nitrogen content in the first silicon nitride(14) under an NH3, an N2O, or an NO gas condition at the temperature of 900deg.C, a second silicon nitride(15) is deposited on the first silicon nitride(14) by a chemical deposition. Then, a second thermal treatment is performed so as to increase a nitrogen content in the second silicon nitride(15). Lastly, a third thermal treatment is performed on the resultant structure so as to form a thin oxide(16) on the second silicon nitride(15) under an NO, or N2O gas condition.
|
