Ion beam synthesis of SiGe alloy layers

Thesis/Dissertation · Sun May 01 00:00:00 EDT 1994

DOI:https://doi.org/10.2172/10165796· OSTI ID:10165796

Im, Seongil ^[1]

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1. Univ. of California, Berkeley, CA (United States)

Procedures required for minimizing structural defects generated during ion beam synthesis of SiGe alloy layers were studied. Synthesis of 200 mm SiGe alloy layers by implantation of 120-keV Ge ions into <100> oriented Si wafers yielded various Ge peak concentrations after the following doses, 2 x 10¹⁶cm^-2, 3 x 10¹⁶cm^-2 (mid), and 5 x 10¹⁶cm^-2 (high). Following implantation, solid phase epitaxial (SPE) annealing in ambient N2 at 800C for 1 hr. resulted in only slight redistribution of the Ge. Two kinds of extended defects were observed in alloy layers over 3 x l0¹⁶cm^-2cm dose at room temperature (RT): end-of-range (EOR) dislocation loops and strain-induced stacking faults. Density of EOR dislocation loops was much lower in alloys produced by 77K implantation than by RT implantation. Decreasing the dose to obtain 5 at% peak Ge concentration prevents strain relaxation, while those SPE layers with more than 7 at% Ge peak show high densities of misfit- induced stacking faults. Sequential implantation of C following high dose Ge implantation (12 at% Ge peak concentration in layer) brought about a remarkable decrease in density of misfit-induced stacking faults. For peak implanted C > 0.55 at%, stacking fault generation in the epitaxial layer was suppressed, owing to strain compensation by C atoms in the SiGe lattice. A SiGe alloy layer with 0.9 at% C peak concentration under a 12 at% Ge peak exhibited the best microstructure. Results indicate that optimum Ge/C ratio for strain compensation is between 11 and 22. The interface between amorphous and regrown phases (a/c interface) had a dramatic morphology change during its migration to the surface. Initial <100> planar interface decomposes into a <111> faceted interface, changing the growth kinetics; this is associated with strain relaxation by stacking fault formation on (111) planes in the a/c interface.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10165796
• Report Number(s): LBL-35580; ON: DE94014958
• Resource Relation: Other Information: TH: Thesis (Ph.D.); PBD: May 1994
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
43 PARTICLE ACCELERATORS
SILICON
ION IMPLANTATION
SILICON ALLOYS
SYNTHESIS
GERMANIUM ALLOYS
GERMANIUM IONS
ION BEAMS
LAYERS
STACKING FAULTS
DISLOCATIONS
INTERFACES
EPITAXY
AMORPHOUS STATE
INTEGRATED CIRCUITS
TRANSISTORS
HETEROJUNCTIONS
426000
360601
665300
COMPONENTS
ELECTRON DEVICES AND CIRCUITS
PREPARATION AND MANUFACTURE
INTERACTIONS BETWEEN BEAMS AND CONDENSED MATTER