TY - JOUR
T1 - Synthesis of butane-like SiGe hydrides
T2 - Enabling precursors for CVD of Ge-rich semiconductors
AU - Chizmeshya, Andrew
AU - Ritter, Cole J.
AU - Hu, Changwu
AU - Tice, Jesse B.
AU - Tolle, John
AU - Nieman, Ronald A.
AU - Tsong, Ignatius S T
AU - Kouvetakis, John
PY - 2006/5/31
Y1 - 2006/5/31
N2 - The synthesis of butane-like (GeH3)2(SiH 2)2 (1), (GeH3)2SiH(SiH3) (2), and (GeH3)2(SiH2GeH2) (3) Si-Ge hydrides with applications in low-temperature synthesis of Ge-rich Si 1-xGex optoelectronic alloys has been demonstrated. The compositional, vibrational, structural, and thermochemical properties of these compounds were studied by FTIR, multinuclear NMR, mass spectrometry, Rutherford backscattering, and density functional theory (DFT) simulations. The analyses indicate that the linear (GeH3)2(SiH2) 2 (1) and (GeH3)2(SiH2GeH 2) (3) compounds exist as a mixture of the classic normal (n) and gauche (g) conformational isomers which do not seem to interconvert at 22 °C. The conformational proportions in the samples were determined using a new fitting procedure, which combines calculated molecular spectra to reproduce those observed by varying the global intensity, frequency scale, and admixture coefficients of the individual conformers. The (GeH3) 2(SiH2)2 (1) species was then utilized to fabricate Si0.50Ge0.50 semiconductor alloys reflecting exactly the Si/Ge content of the precursor. Device quality layers were grown via gas source MBE directly on Si(100) at unprecedented low temperatures 350-450 °C and display homogeneous compositional and strain profiles, low threading dislocation densities, and atomically planar surfaces. Low energy electron microscopy (LEEM) analysis has demonstrated that the precursor is highly reactive on Si(100) surfaces, with H2 desorption kinetics comparable to those of Ge2H6, despite the presence of strong Si-H bonds in the molecular structure.
AB - The synthesis of butane-like (GeH3)2(SiH 2)2 (1), (GeH3)2SiH(SiH3) (2), and (GeH3)2(SiH2GeH2) (3) Si-Ge hydrides with applications in low-temperature synthesis of Ge-rich Si 1-xGex optoelectronic alloys has been demonstrated. The compositional, vibrational, structural, and thermochemical properties of these compounds were studied by FTIR, multinuclear NMR, mass spectrometry, Rutherford backscattering, and density functional theory (DFT) simulations. The analyses indicate that the linear (GeH3)2(SiH2) 2 (1) and (GeH3)2(SiH2GeH 2) (3) compounds exist as a mixture of the classic normal (n) and gauche (g) conformational isomers which do not seem to interconvert at 22 °C. The conformational proportions in the samples were determined using a new fitting procedure, which combines calculated molecular spectra to reproduce those observed by varying the global intensity, frequency scale, and admixture coefficients of the individual conformers. The (GeH3) 2(SiH2)2 (1) species was then utilized to fabricate Si0.50Ge0.50 semiconductor alloys reflecting exactly the Si/Ge content of the precursor. Device quality layers were grown via gas source MBE directly on Si(100) at unprecedented low temperatures 350-450 °C and display homogeneous compositional and strain profiles, low threading dislocation densities, and atomically planar surfaces. Low energy electron microscopy (LEEM) analysis has demonstrated that the precursor is highly reactive on Si(100) surfaces, with H2 desorption kinetics comparable to those of Ge2H6, despite the presence of strong Si-H bonds in the molecular structure.
UR - http://www.scopus.com/inward/record.url?scp=33744818885&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33744818885&partnerID=8YFLogxK
U2 - 10.1021/ja060428j
DO - 10.1021/ja060428j
M3 - Article
C2 - 16719472
AN - SCOPUS:33744818885
SN - 0002-7863
VL - 128
SP - 6919
EP - 6930
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 21
ER -