M11 1, t381 n, e, y 450--600. /}'12 1,13781 n,e [450--600. M13 1,1164 " I 550--600. M14 1,1160 see MI3. M15 1,1390 see Mll. M16 b 1,1173 see M13. M17 1 ...
Journal of Applied Spectroscopy, 1989, Volume 51, Number 2, Pages 797-804
NEAR-EDGE LUMINESCENCE OF IRRADIATED SILICON. THE EFFECT OF THE FORM OF IRRADIATION AND OF THE ANNEALING TEMPERATURE F. P. Korshunov, N. A. Sobolev, and V. A. Sheraukhov
UDC 535.37
When high-energy charged particles, neutrons, and gamma rays interact with silicon crystals, radiation defects (RDs) are created. Irradiation with electrons and gamma rays with energies of several MeV characteristically gives rise to the formation of isolated point defects, consisting of complexes of characteristic defects (vacancies and interstitial atoms) and complexes of the type "defect + impurity." Irradiation with fast neutrons and electrons with E > i0 MeV also brings about the formation of regions of disordering (RD), consisting primarily of divacancies and surrounded by clouds of point defects [i]. There are many publications devoted to the study of radiative recombination (RR) of charge carriers on RDs in silicon. However RR on RDs in the near-edge region of the spectrum(hv = 1.17-~1.0 eV) has been specially studied only in separate works [2-10], while for RDs formed by electron irradiation such studies have been of a preliminary nature [9, ii]. Very little is known about the nature of the corresponding RE centers and the conditions under which they can be observed. In this work the dependence of near-edge RR spectra on the form of irradiation and the annealing temperature of silicon single crystals has been studied in detail. The starting samples were grown by Czochralski's methods (series Nos. 5, 9, and ii), as well as by means of zone melting in a vacuum (series Nos. i, 2, and 4) and in an atmosphere of argon (series Nos. 6-8, i0) or 90% Ar + 10% H 2 (series No. 3). The irradiation was performed by neutrons, electrons, or bremmstrahlung gamma rays. The characteristics of the samples and the parameters of the irradiation are presented in Table i. Both isochronous (15 min) annealing of samples in a furnace (FA) in a quartz boat and pulsed annealing (PA) by radiation from halogen lamps (the duration of the pulses ranged from 6 to 30 sec) were performed. The recombination radiation was excited by an Ar + laser, it was analyzed with a grating monochromator, and it was recorded with the help of a cooled F~U with an S-I photocathode. During the measurements the samples were in a helium cryostat. After irradiation and at different stages of annealing a large number of narrow lines, owing to RR of excitons bound to the RDs and which we denote by the letter M and an order number, as well as the well-studied lines X, W, 12(Y) and Jl, 2 were observed [i0, 12-18]. A list of the lines is given in Table 2. All of them have a half-width < kT at the temperature of the measurements and can be interpreted as being the result of zero-phonon transitions. It was shown previously [8] that most RDs giving rise to the appearance of lines in the series M are apparently isoelectronic centers. For several of the centers presented in Table 2 the symmetry was also determined [i0, 12-15]. We shall study the evolution of the RR spectrum as a function of the FA temperature (TFA) for samples in the series No. 3 (see Fig. i). Figure 2 shows the dependence of the intensity of several of the strongest P~R lines as well as the concentration of divacancies V 2 (measured from the IR absorption in the 1.8 ~m band [19]), the concentration of donor phosphorus atoms (measured from the ratio of the line intensities PTo/EXTo [4]), and the concentration of conduction electrons n (measured with the help of the Hall effect) on TFA. The following five basic stages can be separated in the annealing process. For TAF ~ 3 0 0 ~ the regions of disordering decompose; this is observed based on the annealing of divacancies. In this temperature interval a maximum is reached, the intensity of the line W starts to drop, and the lines X and M4 and the doublet Ji,2 are excited. In the region TFA = 300-400~
1989.
Translated from Zhurnal Pri~ladnoi Spektroskopii, Original article submitted July 21, 1988.
0021-9037/89/5102-0797512.50
Vol. 51, No. 2, pp. 248-256,
9 1990 Plenum Publishing Corporation
August,
797
TABLE i. rameter Sample Iseries, ,No.
Characteristics
N p , cm-3
1
1,3.1014 a
2 3 4 5 6 7 8 9
1,3.1014
of Samples and the Irradiation Pa-
NO, I0 16 cm-3
NC ' 1016 Formand fluence " ( f f , cm"2) of cm-3 irradiation
t
ann, sec
5
n * , 10l~ e, 3.1017
1,5.1015
.~.1 4 60
60
e, 3- 1017 e, 3.1017 e, 3.1017
10
8.1012
