Browsing by Author "Ge, Chung-Hu"

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Characterizing the channel backscattering behavior in nanoscale strained complementary metal oxide semiconductor field-effect transistors
(2006-11-01)
Lin, Hono-Nien
;
Chen, Hung-Wei
;
Ko, Chih-Hsin
;
Ge, Chung-Hu
;
Lin, Horng-Chih
This work investigates the impact of different uniaxial strain polarities on channel backscattering in nanoscale complementary metal oxide semiconductor field-effect transistor (CMOSFET). Two carrier statistics, nondegenerate and degenerate-limited, are employed to extract the channel backscattering ratio, ballistic efficiency, and related backscattering factors. While the channel length scales down and the channel stress level increases further, the modulation of channel backscattering ratio, i.e., improved (degraded) by uniaxial tensile (compressive) strain, becomes more prominent. This observation holds true under both carrier statistics, which implies that the nondegenerate case with simple mathematics can be fairly used for evaluation. In addition, the correlation between strain-enhanced mobility gain and drain current improvement is found to be predicted well by the ballistic efficiency deduced with the nondegenerate carrier statistics.
Correlating drain-current with strain-induced mobility in nanoscale strained CMOSFETs
(2006-08-01)
Lin, Hong-Nien
;
Chen, Hung-Wei
;
Ko, Chih-Hsin
;
Ge, Chung-Hu
;
Lin, Horng-Chih
The correlation between channel mobility gain (Delta mu), linear drain-current gain (AIdlin), and saturation draincurrent gain (Delta I-dsat) of nanoscale strained CMOSFETs are reported. From the plots of Delta I-dlin versus Delta I-dsat and ballistic efficiency (B-sat,B-PSS), the ratio of source/drain parasitic resistance (R-sat,R-PSS) to channel resistance (R-CH,R-PSS) of strained CMOSFETs can be extracted. By plotting Delta mu versus Delta I-dlin, the efficiency of Delta mu translated to Delta I-dlin is higher for strained pMOSFETs than strained nMOSFETs due to smaller R-SD,R-PSS-to-R-CH,R-PSS ratio of strained pMOSFETs. It suggests that to exploit strain benefits fully, the R-SD,R-PSS reduction for strained nMOSFETs is vital, while for strained pMOSFETs the Delta I-dli -to-Delta mu sensitivity is maintained until R-SD,R-PSS becomes comparable to/or higher than R-CH,R-PSS.
Strain-induced channel backscattering modulation in nanoscale CMOSFETs
(2006)
Chen, Hung-Wei
;
Lin, Hong-Nien
;
Ko, Chih-Hsin
;
Ge, Chung-Hu
;
Lin, Horng-Chih
The channel backscattering ratios as well as the ballistic efficiency of strained CMOSFETs were studied for both nondegenerate and degenerate-limited cases. We found that the simple nondegenerate assumption can predict strain-induced change of ballistic efficiency with fair accuracy. The mechanism of drain current dependence on strain-induced mobility change was also investigated based on channel backscattering theory.