Ultrasonic study of point defects in electron-irradiated p-type silicon

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5287684

Johnson, W L

The mechanisms of interaction of ultrasonic waves with point defects in crystals are reviewed, and a perturbation approach is introduced that leads to general expressions for the resonance and relaxation strengths in terms of matrix elements of the ultrasonic perturbation. These expressions provide the basis for a discussion of the polarization dependence of resonance and relaxation. Selection rules for cubic crystals are presented. An exploratory ultrasonic study is performed on electron-irradiated B-doped and Al-doped silicon. Neutral substitutional boron is detected before irradiation, as expected from previous ultrasonic studies on unirradiated silicon. This defect produces both resonance and relaxation. Similar effects are observed for substitutional aluminum. After irradiation, a relaxation is observed when the sample is exposed to 0.18-0.39 eV light. By comparison with previous EPR results, this relaxation is identified as the singly positively charged state of the vacancy, V/sup +/. Preliminary results on the relaxation time and strength of V/sup +/ suggest that it may have several populated vibronic levels. Another relaxation is observed in irradiated Al-doped silicon when the sample is exposed to white light. From its annealing behavior and dopant dependence, it is identified as a nonequilibrium charge state of interstitial aluminum.

• Research Organization: Illinois Univ., Urbana (USA)
• OSTI ID: 5287684
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360605* -- Materials-- Radiation Effects
ACOUSTIC TESTING
ALUMINIUM
BORON
CHARGE STATE
CRYSTAL DEFECTS
CRYSTAL DOPING
CRYSTAL STRUCTURE
ELEMENTS
MATERIALS
MATERIALS TESTING
METALS
NONDESTRUCTIVE TESTING
P-TYPE CONDUCTORS
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
RADIATION EFFECTS
RELAXATION
RESONANCE
SEMICONDUCTOR MATERIALS
SEMIMETALS
SILICON
TESTING
ULTRASONIC TESTING