Role of hydrogen in the permanent passivation of boron-oxygen defects in czochralski silicon

Strong evidence is provided for the critical role of hydrogen in the permanent passivation of boron-oxygen (B-O) defects in silicon. In particular, the impact of rapid thermal processing (firing), plasma exposure and hydrogen-containing dielectrics (PECVD SiNx:H) are explored. Importantly, no B-O passivation is observed in bare-fired wafers, regardless of exposure to hydrogen-rich plasma, whereas wafers with SiNx:H layers present during firing result in significant levels of B-O passivation even at firing temperatures as low as 500 °C, thereby strongly suggesting that hydrogen is directly involved in the passivation mechanism. Implications of such a mechanism are discussed.