Mobility Enhancement in Strained $n$ -FinFETs: Basic Insight and Stress Engineering

Tailoring strain in microelectronic devices

“…• We showed that in FEM simulations the strain in narrow FinFET depends on the fin width, as was shown earlier in measurements [17].…”

“…The strain is induced in plane with the fin/gate metal interface, therefore a narrower FinFET, which has a smaller volume, and approximately equal size interface, can be expected to have a larger amount of strain. Both finite element method (FEM) simulations and holographic interferometry measurements [17] confirm this.…”

“…Parts of the chapter have appeared in [TvH:5] and [TvH:8] . The effect of the strain on the mobility has been investigated [17]. We elaborate on this work by extracting the band offset [18] from the subthreshold characteristics, and investigate the strain dependence on the fin width.…”

“…The strain is strongly compressive and orthogonal to the transport direction. In a silicon FinFET this results in an enhanced carrier mobility [17,24]. In germanium this has a positive effect on the mobility of holes, however, reduces the mobility of electrons slightly [24].…”

Temperature Dependence of Electron Mobility in Uniaxial Strained nMOSFETs

“…The fitting parameters A and B are determined from two limits that D ac,eff at E eff = 0.1MV/cm is 12eV and D ac,eff at 1MV/cm is 18eV, and we used A = 9.34, B = 0.12 for a (100) orientation. Analytical expressions for the strain-induced valley splitting and effective mass changes of the (110)/<110> have been reported in [17]. However, the stress effect of valley and the effective mass in the (100)/<110> have not been explained.…”