Oxide grown on polycrystal silicon by rapid thermal oxidation in N2 O

In this paper, rapid thermal processing (RTP) N2 O polyoxides were studied in terms of oxidation temperature and thickness with O2 oxidation polyoxides as comparison. Atomic force microscopy, transmission electron microscopy, and secondary ion mass spectroscopy measurements were employed to correlate the electrical characteristics with the physical structures. Results showed that RTP N2 O -grown polyoxides exhibited better characteristics on the leakage current, Ebd, trappings and Qbd. It was found that it was the proper amount of nitrogen incorporated in the polyoxide improving the interface of the polyoxide/polysilicon, consequently improving the electrical quality. The initial hole-trapping phenomenon during the constant current stress, which was due to the incorporated nitrogen, was also observed in the N2 O -grown polyoxides. The two-step RTP process, i.e., first RTP oxidizing the polysilicon in O2 and then RTP oxidizing in N2 O, could achieve polyoxide of good characteristics by incorporating the proper amount of nitrogen into the polyoxide.