Background doping of films in molecular beam epitaxy of silicon

Unique results obtained as a result of the development of epitaxial silicon layers with an extremely low concentration of background impurities for infrared photodetectors with blocked impurity photoconduction are analyzed and generalized. Changes in the type and concentration of electrically active background impurities in films grown by molecular beam epitaxy were investigated at all stages in the operation of the system, from initial startup to the fabrication of films having an extremely low level of background impurities <4×1013 cm−3. The laws governing the changes in the type and level of background doping during operation of the system and the mechanism responsible for these changes are established.