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The effect of Young's modulus of contact‐etch‐stop layer (CESL) stressor on the strained‐Si MOSFET
Author(s) -
Chiou YungChuan,
Chen HouYu,
Huang ChienChao
Publication year - 2012
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201200065
Subject(s) - materials science , composite material , substrate (aquarium) , chemical vapor deposition , stress (linguistics) , silicon , silicon nitride , modulus , nitride , layer (electronics) , metallurgy , optoelectronics , linguistics , oceanography , philosophy , geology
Abstract In the analytic solution of residual stresses and bending in multi‐layer/substrate systems, Young's modulus of contact‐etch‐stop layer (CESL) stressor is a potential factor affecting the channel stress of complementary metal–oxide–semiconductor (CMOS) devices. To increase the level of Young's modulus of CESL stressor, the stress level of silicon channels could be boosted at a constant stress level and thickness of CESL as the result of stress simulation. Young's moduli of two widely adopted CESL stressors measured by a nanoindenter instrument, low‐pressure chemical vapor deposition silicon nitride (LP‐SiN) and plasma‐enhanced chemical vapor deposition silicon nitride (PE‐SiN), were 375.7 and 224.7 GPa, respectively. As a result of stress stimulation, the channel stress induced by LPSiN CESL could increase 30% higher than that of PE‐SiN CESL. Through the use of a tensile 1 GPa CESL stressor for the 90 nm n‐FETs, an extra 4% enhancement in drive current I D,sat was obtained in the device with an LP‐SiN CESL as compared to that with PE‐SiN. The electrical data is in good agreement with the prediction of the stress simulation.