B-doped fully strained Si{sub 1{minus}{ital x}}Ge{sub {ital x}} layers grown on Si(001) by gas-source molecular beam epitaxy from Si{sub 2}H{sub 6}, Ge{sub 2}H{sub 6}, and B{sub 2}H{sub 6}: Charge transport properties

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.363407· OSTI ID:383739

Lu, Q; Sardela, Jr, M R; Bramblett, T R; Greene, J E ^[1]

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1. Materials Science Department, Engineering Science Laboratory and the Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)

B-doped Si{sub 1{minus}{ital x}}Ge{sub {ital x}} layers with Ge fractions, determined by Rutherford backscattering spectroscopy, ranging from 0 to 0.28 and B concentrations, from quantitative secondary-ion spectroscopy measurements, between 5{times}10{sup 16} and 4{times}10{sup 19} cm{sup {minus}3} were grown on Si(001) at temperatures {ital T}{sub {ital s}}=475{endash}575{degree}C by gas-source molecular beam epitaxy from Si{sub 2}H{sub 6}, Ge{sub 2}H{sub 6}, and B{sub 2}H{sub 6}. Film thicknesses ranged from 200 nm for alloys with {ital x}=0.28 to 800 nm with {ital x}=0.05 to 1.4 {mu}m for Si. Structural analyses by high-resolution x-ray diffraction and reciprocal lattice mapping combined with transmission electron microscopy showed that all films were fully strained, with measured relaxations of only {approx_equal}4{times}10{sup {minus}5}, and exhibited no evidence of dislocations or other extended defects. The hole conductivity mobility {mu}{sub {ital c},{ital h}} in these layers increased continuously with increasing Ge concentrations, whereas the Hall mobility decreased yielding a Hall scattering factor that ranged from 0.75 for Si to 0.26 for Si{sub 0.72}Ge{sub 0.28} but was not strongly affected by B concentration. {mu}{sub {ital c},{ital h}}, with {ital C}{sub B}=2{times}10{sup 18} cm{sup {minus}3}, varied from 110 cm{sup 2}V{sup {minus}1}s{sup {minus}1} for Si{sub 0.95}Ge{sub 0.05} to 158 cm{sup 2}V{sup {minus}1}s{sup {minus}1} for Si{sub 0.72}Ge{sub 0.28}, compared to 86 cm{sup 2}V{sup {minus}1}s{sup {minus}1} for Si, in good agreement with Boltzmann transport model calculations accounting for changes in the valence-band structure due to the effects of both alloying and biaxial in-plane compressional strain. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: University of Illinois
• DOE Contract Number: AC02-76ER01198
• OSTI ID: 383739
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 80; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ADDITIONS
CARRIER MOBILITY
CRYSTAL STRUCTURE
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRON MICROSCOPY
GERMANIUM SILICIDES
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
MOLECULAR BEAM EPITAXY
RBS
STRAINS
X-RAY DIFFRACTION
XRD