| 摘要 |
A gate insulating film ( 13 ) and a gate electrode ( 14 ) of non-single crystalline silicon for forming an NMOS transistor are provided on a silicon substrate ( 10 ). Using the gate electrode ( 14 ) as a mask, n-type dopants having a relatively large mass number (70 or more) such as As ions or Sb ions are implanted, to form a source/drain region of the NMOS transistor, whereby the gate electrode ( 14 ) is amorphized. Subsequently, a silicon oxide film ( 40 ) is provided to cover the gate electrode ( 14 ), at a temperature which is less than the one at which recrystallization of the gate electrode ( 14 ) occurs. Thereafter, thermal processing is performed at a temperature of about 1000° C., whereby high compressive residual stress is exerted on the gate electrode ( 14 ), and high tensile stress is applied to a channel region under the gate electrode ( 14 ). As a result, carrier mobility of the NMOS transistor is enhanced.
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