Spin 1 centers in neutron irradiated silicon

Conference · Fri Mar 01 04:00:00 EST 1963

OSTI ID:4875217

Jung, Wun; Newell, G. S.

Electron paramagnetic resonance was used to identify a number of fast-neutron induced defects formed in pile irradiated Si and to follow their concentrations as a function of annealing. Measurements were made at 300, 77, and 4.2 deg K on samples that had attained intrinsic resistivity during irradiation, using superheterodyne spectrometers operating at 24 kMc and 9.4 kMc. Aside from the Si-N center, the most prominent lines of the spectrum arise from the m/sub s/ = O to plus or minus 1 transitions of four spin 1 systems. The distinct symmetry and small production rate ( approximately 0.05 centers per fast neutron collision) indicate a class of well-defined but relatively rare defects. Their g tensors, zero-field splitting tensors, and hfs are compatible with systems having two weakly interacting (1 1 1) dangling bonds separated by about a lattice spacing, giving the S = 1 Hamiltonians in the triplet levels formed by the weak exchange interaction. Low-temperature measurements suggest that the singlet-triplet splitting lies between 3 and 50 cm^-1. Comparison with floating zone Si shows Center (11, 111), which is dominant in unannealed samples, to be independent of impurity. The remaining three S = 1 centers, which grow and decay rapidly at higher temperatures, involve O. Precise measurements of the parameters of the spin Hamiltonians are given to permit reproducible identification of the centers. (auth)

• Research Organization: Purdue Univ., Lafayette, IN (United States)
• NSA Number: NSA-17-031038
• OSTI ID: 4875217
• Report Number(s): CONF-23--7; AED-Conf--022-26
• Country of Publication: United States
• Language: English

Related Subjects

ANNEALING
CONFERENCE
DEFECTS
FAST NEUTRONS
INTERACTIONS
LATTICES
MAGNETIC RESONANCE
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
RADIATION EFFECTS
REACTORS
SILICON
SPECTRA
SPECTROMETERS
SPIN
TEMPERATURE