Nanoscale strained-Si/SiGe and double-gate MOSFET modeling

Abstract

Seamless transition of devices across various topologies. 17 2.2 Piecewise (crosses) fc solutions, compared with iterative solution 23 (circle). 2.3 Piecewise (crosses) and unified regional (lines) $> solutions, compared 26 with iterative solution (circle). 2.4 Unified regional </> s solutions and the combined solutions </> sa 26 (accumulation/depletion) and t/> se ff(d\\ region) as well as its l st /2 n-order derivatives (inset). 2.5 The derivatives of Qb and its regional components with respective to 29 V g b and the inset shows smoothness of Cb g. 2.6 Unified regional bulk charge in accumulation (Qb.acc) and 31 depletion/inversion (Qb.ds) and the F^-dependent component (-C 0X Db"d). The inset shows tuning for charge neutrality at flat band. 2.7 Channel, drain, source capacitances from the derivatives of Q t , Qj, Q s 32 (inset), compared with Medici data (symbols). 3.1 The lattice structure of relaxed SiGe (top) and silicon (bottom). 35 3.2 Strained silicon on top of relaxed SiGe region. 36 3.3 Strain in silicon layer relieved due to misfit dislocations as it is grown 36 above the critical thickness. vii ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library 3.4 (a) A six-fold degenerate silicon conduction-band minima (b) the two 37 dark ellipsoids are up in energy while the four white ellipsoids are down in energy, (c) The two perpendicular ellipsoids are down in energy while the four ellipsoids are up in energy. 3.5 Valence band under different strain condition. Strain is found to 38 remove the degeneracy between the LH band and the HH band. 3.6 Band offset between compressively strained Sio.7Geo.3 and silicon. 3.7 Band offset between tensile strained-Si and relaxed SiGe. 3.8 Calculated drift velocity at high electric field in strained and unstrained-Si. 3.9 Layer structures of strained-Si based nMOS devices 3.10 Layer structures of strained-Si based pMOS devices. 3.11 The maximum transconductance V, definition and I crit @ V t0 , used in the constant current definition. 3.12 Schematic of a surface channel strained-Si nMOSFET. 3.13 Schematic of a buried channels strained-Si nMOSFET. 3.14 Direct playback of the bulk charge model from bulk for x = 0.3, compared with Medici (circle), which shows the model missing the "plateau" and inaccuracy in the depletion region. 3.15 Hole concentrations (left axis) and surface potentials (right axis) at the 59 Si/Sic^ (solid) and Si/SiGe (dotted) interfaces extracted from the Medici device. Calculated VFBI and V FB 2 correspond directly to the viii ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library numerically probed device parameters. 3.16 Band diagrams of the Medici device near the two calculated V FBI and 60 VFB2 gate-bias conditions, further supporting the definitions and physics built into the model (which physically relates to x, tsu and N Si parameters) 3.17 The two interpolation functions in relation to the two flat-band voltages 63 and AVj...