Polysilicon films deposited by low-pressure chemical vapor deposition (LPCVD) exhibit large residual stress and stress gradient, depending on the deposition condition. An in situ growth method based on multi-layer concept is presented to control the property for as-deposited polysilicon. A 3-?m-thick polysilicon film with nine layers structure is demonstrated under the detailed analysis of multi-layer theory and material characteristic of polysilicon. The results show that a 3-?m-thick polysilicon film with 8-MPa overall residual tensile stress and 2.125-MPa/?m stress gradient through the film thickness is fabricated successfully.
© 2005 Chinese Optics LettersPDF Article