A Variety of Oxygen-Induced Recombination Centres in 450 to 600 °C Heat-Treated Silicon

Abstract

Recombination centres for excess carriers containing from four to seven oxygen atoms (besides the known ones containing eight oxygen atoms) are effectively formed in 450 to 600 °C heat‐treated oxygen‐rich n‐type silicon. An analysis of the formation kinetics of the species found in dependence on the oxygen content permits to find the solubility of the recombination‐efficient oxygen‐containing centres and the rates of their formation and dissociation. Some unknown nuclei in the starting material (they govern the reaction constants for the appearance and annihilation of the species studied) are responsible for the dominant formation of one (or another) kind of the oxygen‐containing recombination centres observed.

Long‐lifetime photoconductivity in Cz n‐ and p‐Si

“…So the actual ORC structure and the ORC electrical characterization depend not only on the number of oxygen atoms they include but also on some other important factors such as the nuclei the ORC are formed on, the "impurity" environment and secondary defects near them (the last arise due to a rather large ORC size). The above stated results in the facts that, on the one side, the ORC of the same oxygen content manifest themselves as "different" (as concerns the recombination efficiency for the electron, hole capture) defects (species), and, on the other, the ORC nuclei origin fixes not only the resulting ORC size (the number of oxygen atoms the ORC contains (GLINCHUK et al 1986)), but the resulting ORC electrical characterisation too.…”

“…Electrical activity of oxygen atoms appears as they become clustered due to heat-treatment induced diffusion a t temperatures around and above 450 "C ( WATKINS). So oxygen-induced recombination centres (ORC) are effectively formed in heat treated a t 450 to 650 "C Cz-Si (GLINCHUK et al 1986). Below we will show that when both heat-treated Cz n-and p-Si crystals are excited by a light pulse (the excess free electrons and holes are generated) the long-lifetime photoconductivity (it persists for tens of seconds and even minutes after the illumination is switched off) appears due to a slow recombination of majority carriers via ORC and discuss a model to explain it.…”

“…Much work is devoted a t present t o the investigation of the electrical activity of oxygen atoms in Czochralski-grown silicon (Cz-Si) as this impurity has interesting physical properties and is important in silicon technological applications (see, for example, GLINCHUK et al 1985GLINCHUK et al , 1986; WATKINS). The present paper is also aimed a t understanding the oxygen-related effects in Cz-Si.…”