Stress Engineering Using Si3N4 for Stiction Free Release of SOI Beams
We report on the effect of thin silicon nitride (Si3N4) induced tensile stress on the structural release of 200 nm thick SOI beam, in the surface micro-machining process. A thin (20 nm/100 nm) LPCVD grown Si3N4 is shown to significantly enhance the yield of released beam in wet release technique. This is especially prominent with increase in beam length, where the beams have higher tendency for stiction. We attribute this yield enhancement to the nitride induced tensile stress, as verified by buckling tendency and resonance frequency data obtained from optical profilometry and laser doppler vibrometry.
KeywordsFixed–fixed beam Buckling distance Yield Tensile stress SOI
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We thank MCIT for funding support. We would like to thank the Fabrication facility, Staff and Characterization facility and Staff at CeNSE, IISc. We would like to thank Sreekanth for helping us with vibrometer experiments.
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