Oxide precipitate nucleation at 300 °C in low resistivity n-type Czochralski Si

Abstract

Oxide precipitate nucleation at 300 °C in low resistivity As or Sb doped Czochralski Si is studied with and without prior rapid thermal processing (RTP). With prior RTP, a subsequent nucleation anneal even at 300 °C, leads to a high oxide precipitate density after a precipitation anneal at 1000 °C. As this is not observed without prior RTP, the effect is assumed to be related to the introduction of vacancies by RTP. As and Sb are deactivated by the formation of Asx–V or Sbx–V complexes. The reduction of free carriers causes an increase of resistivity corresponding with a few times 1017 cm−3 deactivated dopant atoms suggesting that about 1017 cm−3 vacancies are frozen-in after RTP. During subsequent annealing at 300 °C, the resistivity recovers to its original value due to the release of vacancies that can facilitate homogeneous oxide precipitate nucleation or can lead to the formation of VO2 and As–V–O or Sb–V–O complexes acting as heterogeneous nucleation centers that can grow further during subsequent anneals.