Electron microscopy studies of ion implanted silicon

Thesis/Dissertation · Fri Oct 31 23:00:00 EST 1975

DOI:https://doi.org/10.2172/4084743· OSTI ID:4084743

Seshan, Krishna ^[1]

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

The nature of defects resulting from the implantation of phosphorous ions into doped silicon and a model of how they form are reported. This involved an electron microscope study of the crystallographic defects (in the 300A size range in concentration of 10¹⁵/cm³) that form upon annealing. Images formed by these crystallographic defects are complex and that nonconventional imaging techniques are required for their characterization. The images of these small defects (about 300A) are sensitive to various parameters, such as foil thickness, their position in the foil, and diffracting conditions. The defects were found to be mostly interstitial hexagonal Frank loops lying on the four [111] planes and a few perfect interstitial loops; these loops occurred in concentrations of about 10¹⁶/cm³. In addition, ''rod like'' linear defects that are shown to be interstitial are also found in concentrations of 10¹³/cm³. It was found that the linear defects require boron for their formation. A model is proposed to account for the interstitial defects. The number of point defects that make up the defects is of the same order as the number of implanted ions. The model predicts that only interstitial loops ought to be observed in agreement with several recent investigations. Dislocation models of the loops are examined and it is shown that phosphorous ions could segregate to the Frank loops, changing their displacement vectors to a/x[111]. (x > 3) thus explaining the contrast effects observed. It would also explain the relative electrical inactivity of P⁺ ion implants.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Energy Research and Development Administration (ERDA)
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-33-020868
• OSTI ID: 4084743
• Report Number(s): LBL--2728
• Country of Publication: United States
• Language: English

Related Subjects

*SILICON-- PHYSICAL RADIATION EFFECTS
36 MATERIALS SCIENCE
ANNEALING
ANTIMONY ADDITIONS
BORON ADDITIONS
DISLOCATIONS
DOPED MATERIALS
ELECTRICAL PROPERTIES
ELECTRON DIFFRACTION
ELECTRON MICROSCOPY
IMAGES
INTERSTITIALS
ION BEAMS
KEV RANGE 10- 100
PHOSPHORUS ADDITIONS
PHOSPHORUS IONS
POINT DEFECTS
SCREW DISLOCATIONS