Solid-State Electronics, Vol.53, No.11, 1177-1182, 2009
1/f noise study on strained Si0.8Ge0.2 p-channel MOSFETs with high-k/poly Si gate stack
The study of the low frequency (1/f) noise of strained Si0.8Ge0.2 p-channel MOSFETs with poly Si/HfSiOx gate stacks is presented. Apart from the reduced threshold voltage, improved maximum transconductance and increased low-field mobility offered by the strained SiGe, the I If noise was observed to be considerably lower than in the Si control devices. The 1/f noise characteristics were likely originated by carrier number fluctuations (Delta n model) for both the strained SiGe and Si control pMOSFETs. This is consistent with the proposed model for high-k MOSFETs based on correlated number-mobility fluctuations theory. Despite the much worse high-k gate stack quality characterized by gate leakage and charge pumping. the relative reduction (up to 10x) in the noise for the strained SiGe over Si control with high-k is preserved. as was observed in the past for strained SiGe and Si control devices having SiO2 gate dielectric, likely attributed to the existence of the Si cap layer. (C) 2009 Elsevier Ltd. All rights reserved.