摘要 |
A method for forming a thin film structure, which has small tensile stress due to controlled mechanical stress, and is made to be conductive, is provided. A lower film including polysilicon thin film is formed on a substrate such as Si substrate, then an impurity such as P is doped into the lower film and thermally diffused, thereby the lower film is made conductive. Then, an upper film is deposited on the lower film, the upper film including a polysilicon thin film that is simply deposited and not made to be conductive. The upper film has a tensile stress in an approximately the same level as compressive stress of the lower film, and a thin film structure as a whole, the structure including the lower film and the upper film, is adjusted to have small tensile stress.
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