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Title: Spatially resolved localized vibrational mode spectroscopy of carbon in liquid encapsulated Czochralski grown gallium arsenide wafers

Substitutional carbon on an arsenic lattice site is the shallowest and one of the most dominant acceptors in semi-insulating Liquid Encapsulated Czochralski (LEC) GaAs. However, the role of this acceptor in determining the well known W'' shape spatial variation of neutral EL2 concentration along the diameter of a LEC wafer is not known. In this thesis, we attempt to clarify the issue of the carbon acceptor's effect on this W'' shaped variation by measuring spatial profiles of this acceptor along the radius of three different as-grown LEC GaAs wafers. With localized vibrational mode absorption spectroscopy, we find that the profile of the carbon acceptor is relatively constant along the radius of each wafer. Average values of concentration are 8 {times} 10E15 cm{sup -3}, 1.1 {times} 10E15 cm{sup -3}, and 2.2 {times} 10E15 cm{sup -3}, respectively. In addition, these carbon acceptor LVM measurements indicate that a residual donor with concentration comparable to carbon exists in these wafers and it is a good candidate for the observed neutral EL2 concentration variation. 22 refs., 39 figs.
Authors:
Publication Date:
OSTI Identifier:
5398032
Report Number(s):
LBL-25790
ON: DE90003121; TRN: 89-031567
DOE Contract Number:
AC03-76SF00098
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis (M.S.)
Research Org:
Lawrence Berkeley Lab., CA (USA)
Sponsoring Org:
DOE/ER
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; GALLIUM ARSENIDES; CARBON ADDITIONS; SEMICONDUCTOR MATERIALS; ABSORPTION SPECTROSCOPY; BAND THEORY; CHARGE STATE; CRYOSTATS; FERMI LEVEL; INTERFEROMETERS; PHOTOCONDUCTORS; SPECTROMETERS; VIBRATIONAL STATES; ALLOYS; ARSENIC COMPOUNDS; ARSENIDES; CONTROL EQUIPMENT; ENERGY LEVELS; EQUIPMENT; EXCITED STATES; GALLIUM COMPOUNDS; MATERIALS; MEASURING INSTRUMENTS; PNICTIDES; SPECTROSCOPY; THERMOSTATS 656002* -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-); 360201 -- Ceramics, Cermets, & Refractories-- Preparation & Fabrication