Chinese Optics Letters, Vol. 2, Issue 8, 08489 (2004)
An in situ growth method for property control of LPCVD polysilicon film
Hongbin Yu, Haiqinq Chen, Jun Li, and Chao Wang
- Department of Optoelectronics Engineering, Huazhong University of Science and Technology, Wuhan 430074
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-μm-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-μm-thick polysilicon film with 8-MPa overall residual tensile stress and 2.125-MPa/μm stress gradient through the film thickness is fabricated successfully.