Atomistic structure and strain relaxation in Czochralski-grown SixGe1−x bulk alloys

Temperature dependence of electron and hole mobilities in heavily impurity-doped SiGe single crystals

“…19 A similar behavior of the acceptor states is likely. Here, it can be noted that SiGe is an imperfect Pauling-type material, 20,21 that is, the local atomistic structure is accommodated by the changes of both the bond lengths and bond angles.…”

Structural Properties

“…Recent EXAFS and XRD studies performed on strained Si x Ge 1Àx /Si layers indicated that the Si-Si, Si-Ge and Ge-Ge nearest-neighbor distances are 2.35 AE 0.02, 2.42 AE 0.02 and 2.38 AE 0.02 A , respectively, close to the sum of their constituent-element covalent radii and independent of x, while the lattice constant varies monotonically with x [16,17]. More recently, Yonenaga et al [18] investigated the local atomistic structure in bulk Czochralski-grown Si x Ge 1Àx using EXAFS. As shown in Figure 1.9, the bond lengths Si-Si, Si-Ge and Ge-Ge in the bulk Si x Ge 1Àx remain distinctly different lengths and vary in linear fashion of x over the entire composition range 0 x 1.0, in agreement with expectation derived from ab-initio electronic structure calculation.…”

“…Near-neighbor distance in Si x Ge 1Àx at 300 K. The experimental data are taken from Yonenaga et al[18]. The horizontal lines show the bond lengths in bulk Si and Ge.…”

“…18 Near-neighbor distances versus x for w-Ga x In 1Àx N. The experimental data were measured at 300 K by Jeffe et al[30]. The theoretically calculated lines are taken from Mattila and Zunger[31] who used the valence force field simulation with large supercells (512-1280 atoms) 17 Near-neighbor distance in Ga x In 1Àx P y As 1Ày /InP at 300 K. The experimental data are taken from Oyanagi et al[29].…”

Carrier Mobility and Resistivity of n- and p-Type SixGe1-x (0.93<x<0.96) Single Crystals

“…As reported in our recent paper, 2) the rate-controlling scattering mechanisms are also supposed to be more complicated than those previously conceived for the atomistic structure of SiGe alloys of the imperfect Pauling-type. 3) This author's group has grown large-sized bulk single crystals of Si x Ge 1Àx alloy over the entire composition range of 0 < x < 1 by the Czochralski growth method and is investigating various fundamental properties, including electrical transport parameters, of these high-quality single crystals. 2,4) We report herein the dependence of carrier mobility and resistivity on the carrier concentration in undoped and highly conductive n-and p-type SiGe single crystals with x ¼ 0:93 { 0:96 at room temperature in order to provide these data as fundamental knowledge of the system.…”