Abstract
The effect of oxygen concentration on recombination lifetimes 
in as‐grown as well as oxidized magnetic Czochralski (MCZ) silicon was investigated. Oxygen concentration was varied in the range of 5–10 ppm within the same ingot by changing the crucible rotational speed. Injection‐sensitive photoconductive decay (PCD) technique was used to measure lifetime 
and to quantify Shockley‐Read‐Hall recombination, trap‐assisted Auger recombination coefficient 
, and band‐to‐band Auger recombination coefficient 
. Recombination lifetime at an injection level of 
in as‐grown MCZ wafers was as high as 2.1 ms and was found to be independent of interstitial oxygen concentration up to 10 ppm. Contrary to the 
at relatively lower injection level, the lifetime at moderate injection level of
was found to decrease with increasing oxygen concentration due to the increase in trap‐assisted Auger recombination coefficient 
. It is also shown for the first time that the trap‐assisted Auger coefficient 
increases monotonically with the oxygen concentration in MCZ silicon. The lifetimes in the oxidized wafers, measured at lower as well as moderate injection levels, showed a decrease with increasing oxygen concentration. The degradation in lifetime at lower injection level was attributed to the interaction between oxygen and diffused‐in impurities during high‐temperature processing. After oxidation, a substantial increase in the 
coefficient was observed at all oxygen levels. However, band‐to‐band Auger recombination coefficient 
was found to be independent of oxygen concentration, both before and after oxidation.