Distribution of point defects in Si(100)/Si grown by low-temperature molecular-beam epitaxy and solid-phase epitaxy
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- AT T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)
Positron annihilation in Si is a quantitaive, depth-sensitive technique for the detection of vacancylike defects or voids. A sensitivity of 5[times]10[sup 15] cm[sup [minus]3] for voidlike defects is easily achieved. The technique has been applied to a study of point-defect distributions in thin films of Si grown by molecular-beam epitaxy. A special procedure was developed to remove the influence of the native oxide on the positron measurement. 200-nm-thick films grown at temperatures between 475 and 560 [degree]C show no defects below the sensitivity limit and are indistinguishable from the bulk substrate. So are films grown at 220 [degree]C, provided a 2-min high-temperature anneal to a peak temperature of [ge]500 [degree]C is executed every [congruent]30 nm during growth. If [ital T][sub RTA]=450 [degree]C, part of the film contains vacancylike defects to a concentration of [congruent]10[sup 18] cm[sup [minus]3]. These results correlate well with current-voltage characteristics of [ital p]-[ital n] junctions grown with different rapid thermal anneal (RTA) temperatures. Ion scattering, with a defect sensitivity of [approx]1%, shows no difference between films grown with different [ital T][sub RTA]. Recrystallization of amorphous films, deposited at room temperature and annealed [ital in] [ital situ] at 550 [degree]C, always leaves a significant defect concentration of [congruent]2[times]10[sup 18] cm[sup [minus]3]; those defects are reduced but still present even after a 2-h 800 [degree]C furnace anneal.
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6238109
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 48:8; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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