Title :
A sticking model of suspended polysilicon microstructure including residual stress gradient and postrelease temperature
Author :
Yee, Youngjoo ; Park, Myoungkyu ; Chun, Kukjin
Author_Institution :
Sch. of Electr. Eng., Seoul Nat. Univ., South Korea
fDate :
9/1/1998 12:00:00 AM
Abstract :
A sticking (stiction) model for a cantilevered beam is derived. This model includes the effect of the bending moment, which stems from stress gradient along the vertical direction of structural polysilicon, and the temperature during the release process. The bending moment due to the stress gradient will play an important role in evaluating antisticking efficiency since liquid tension and surface energy of microstructures tend to become smaller by newly developed antisticking techniques. The effects of stress gradient and temperature were analyzed and verified with surface-micromachined polysilicon cantilevers. By modifying the substrate polysilicon with grain-hole formation technique, the effects of residual stress gradient in polysilicon on stiction could be observed in the condition of low work of adhesion
Keywords :
adhesion; bending; elemental semiconductors; internal stresses; micromachining; micromechanical devices; modelling; silicon; surface tension; Si; adhesion; antisticking efficiency evaluation; bending moment; cantilevered beam; grain-hole formation technique; postrelease temperature; residual stress gradient; sticking model; stiction model; substrate polysilicon modification; surface-micromachined polysilicon cantilevers; suspended polysilicon microstructure; Micromachining; Microstructure; Residual stresses; Rough surfaces; Structural beams; Substrates; Surface roughness; Surface tension; Surface treatment; Temperature;
Journal_Title :
Microelectromechanical Systems, Journal of