THERMAL-ACTIVATION SPECTROSCOPY OF SMALL QUANTITIES OF SHALLOW SECONDARY IMPURITIES IN SLIGHTLY COMPENSATED, DOPED SILICON

The capabilities of the thermally stimulated conduction method for the detection of small quantities of shallower secondary impurities relat ive to the primary donor impurity are investigated using Si:Ga with do ping level (2-3) x 10(16) cm(-3) and a low content of residual impurit ies, less than or equal to 10(13) cm(-3). The thermally stimulated con ductivity is measured in the temperature range T = 4.2-24 K in warming electric fields E = 200-300 V/cm after photostimulation of the sample s by radiation front the impurity absorption band. At T similar or equ al to 18 K, the, thermally stimulated conduction curves reveal a peak, which is shown to be associated with thermal depopulation of the boro n secondary impurity levels. It is also shown that the thermally stimu lated conduction method is highly efficient in the presence of linear recombination for establishing the chemical nature of secondary impuri ties, for determining their concentration, and for investigating the i nfluence of strong electric fields on their parameters. (C) 1996 Ameri can Institute of Physics.