| 摘要 |
PURPOSE:To thin off a triple-layer film by a method wherein, after an SiN film has been formed, the SiN film is modified by annealing in the N2 atmosphere containing NH3, and the oxygen permeability of the SiN film when an SiO2 film is formed on the SiN film is decreased. CONSTITUTION:A silicon substrate is thermally oxidized in dry oxygen or in the dry oxygen containing HCI, and after a thermally oxidized film 2 of 35 Kt has been formed, an SiN film 3 of about 30 Kt is formed thereon. Then, an annealing process is performed thereon at 1000 deg.C or above in the atmosphere containing 5% or more of NH3 for N2. The SiN film is modified in the N2 atmosphere containing NH3 by performing the above-mentioned method. As a result, an SiN film which transmits no oxygen when the thermally oxidized film is formed on the SiN film, can be obtained and the thinning off of an SiO2/ SiN/SiO2 film can also be achieved.
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