Point defects in Si thin films grown by molecular beam epitaxy

Journal Article · Mon Aug 03 04:00:00 EDT 1992 · Applied Physics Letters; (United States)

DOI:https://doi.org/10.1063/1.107881· OSTI ID:7201624

Gossmann, H ^[1]; Asoka-Kumar, P; Leung, T C; Nielsen, B; Lynn, K G ^[2]; Unterwald, F C; Feldman, L C ^[1]

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1. AT T Bell Laboratories, Murray Hill, New Jersey 07974 (United States)
2. Brookhaven National Laboratory, Physics Department, Upton, New York 11973 (United States)

Depth profiles of vacancylike defects have been determined by positron annihilation spectroscopy in 200-nm-thick Si films grown by molecular beam epitaxy on Si(100) substrates at growth temperatures {ital T}{sub growth}=200--560 {degree}C. The line shape of the radiation emitted from implanted positrons annihilating in the near-surface region of a solid gives quantitative, depth-resolved information on defect concentrations in a nondestructive way. In particular, the method is sensitive to vacancylike defects in a concentration range inaccessible to electron microscopy or ion scattering, but important for electrical device characteristics. The sensitivity limit for these defects in the present experiments is estimated as 5{times}10{sup 15} cm{sup {minus}3}. Films grown at {ital T}{sub growth}{ge}475{plus minus}20 {degree}C are indistinguishable from virgin wafers. So are samples with {ital T}{sub growth}=220{plus minus}20 {degree}C, subjected to a 2 min, {ital T}{sub RTA}{approx gt}500 {degree}C rapid thermal anneal (RTA) after every {approx}30 nm of Si growth. If {ital T}{sub RTA}=450{plus minus}20 {degree}C, part of the film contains a concentration of vacancylike defects on the order of 10{sup 18} cm{sup {minus}3}. Our results indicate the importance of the growth parameters, such as temperature and substrate preparation, for the production of high quality films.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7201624
• Journal Information: Applied Physics Letters; (United States), Journal Name: Applied Physics Letters; (United States) Vol. 61:5; ISSN APPLA; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
665100 -- Nuclear Techniques in Condensed Matter Physics -- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
ANNIHILATION
BASIC INTERACTIONS
BEAMS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTROMAGNETIC INTERACTIONS
ELEMENTS
EPITAXY
HEAT TREATMENTS
INTERACTIONS
LEPTON BEAMS
MOLECULAR BEAM EPITAXY
PARTICLE BEAMS
PARTICLE INTERACTIONS
POINT DEFECTS
POSITRON BEAMS
RESOLUTION
SEMIMETALS
SENSITIVITY
SILICON
SPATIAL RESOLUTION
TEMPERATURE EFFECTS
VACANCIES