Deep levels are found in n-type silicon that is annealed in N2 and quenched to room temperature. The energy level and capture cross section of the deep levels are estimated to be about E c-0.42 eV and of the order of 10-17 cm2, respectively. The charge state of the deep levels is determined to be acceptor type by measuring the temperature dependence of the Schottky junction capacitance made in the specimen with the deep levels. The depth profile of the deep level density is found to correspond to that of the complementary error function, and the diffusion coefficient calculated from the profile is in good agreement with that of nitrogen in silicon. It is assumed that generation of deep levels is due to the formation of nitrogen-vacancy complexes, because quenching to room temperature and several hours' storage after quenching are required to form the deep levels. In order to confirm this assumption, we attempted to control the deep level density by changing the vacancy concentration. Oxidation of the specimen surface and formation of oxygen precipitates in silicon are known to decrease the vacancy concentration, since they supply excess interstitials from the oxide and silicon interface. Experimental results clearly show that the deep level density observed in these specimens is very low.

No abstract

RTP will be replaced with some of the conventional thermal processing employed in ULSI fabrication lines in near future. We show at first the device characteristics demanded for next generation DRAM which is a typical example of ULSIs and some issues to satisfy the demands. Next we show some candidates for RTP in the ULSI processes and discuss difference between RTP and the conventional thermal processes. We think one of the largest difference is the quenching Si wafers after short time annealing and by the quenching the deep levels due to fast diffusing atoms and point defects in Si are introduced. Experimental results of N2 and Cu related deep levels are shown as the examples of the deep levels induced by the quenching in Si. Finally, we propose the gettering method for them in RTP.