Control of stresses in highly doped multilayer polysilicon structures used in MEMS applications

Longqing Chen; Li Hui Guo; Jianmin Miao; Rongming Lin

doi:10.1117/12.424411

6 April 2001 Control of stresses in highly doped multilayer polysilicon structures used in MEMS applications

Longqing Chen, Li Hui Guo, Jianmin Miao, Rongming Lin

Proceedings Volume 4234, Smart Materials; (2001) https://doi.org/10.1117/12.424411
Event: Smart Materials and MEMS, 2000, Melbourne, Australia

Abstract

Influence of LPCVD deposition condition, substrate, film thickness, crystallized degree and pre-annealing on residual stress in LPCVD polysilicon films was studied. The polysilicon deposited on PSG substrate shows the lowest residual stress. The relationship between crystallized degree of polysilicon films and the film thickness was investigated with the aid of Raman Scattering Spectrum. The residual stress shows a significant dependence on the film thickness because crystallized degree raises with the film thickness increase. The test results show that (1) for a thinner film (0.20 micrometer), even if to use a higher deposition temperature (630 degrees Celsius), its crystallized degree is still quite low and a quite higher residual tensile stress is resulted in the film. (2) for a thick film (4 micrometer), even if to use a lower deposition temperature (580 degrees Celsius), a significant crystallization still will occur in as-deposited films and a residual tensile stress is resulted in the films. A pre-annealing step before polysilicon boron doping is brought into the fabrication process of multi-layer diaphragm structure. It can be used as a method to control stress in highly doped polysilicon films. The stress control test of highly boron doped polysilicon/oxide diaphragm structure was carried out. The result shows that the property and magnitude of the stresses in highly boron doped polysilicon-oxide diaphragm can be arbitrarily changed in certain range by varying the holding time of final annealing.

Citation Download Citation

Longqing Chen, Li Hui Guo, Jianmin Miao, and Rongming Lin "Control of stresses in highly doped multilayer polysilicon structures used in MEMS applications", Proc. SPIE 4234, Smart Materials, (6 April 2001); https://doi.org/10.1117/12.424411

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available