In this paper, the key parameters of a rapid thermal annealing (RTA) nitriding step are discussed with respect to vacancy‐ and oxygen precipitate (BMD)‐profile formation. These RTA key performance parameters are the maximum NH3 dissociation temperature (i), the temperature stability of the stored vacancy peak (ii), and the defect dissolution capability of self Si agglomerates at elevated temperatures (iii). This parameter study could be helpful for a future model of the vacancy in‐diffusion process into the Si near surface region. Especially the gate oxide integrity (GOI) is an important parameter to establish long life cycles in current memory devices. After NH3 RTA processing, it was surprisingly found that the GOI defect level is still influenced by small‐sized grown in particles. It is demonstrated that a complete restoration toward a high GOI signal can be achieved via a 1300 °C RTA step. The gate oxide integrity is afterwards as good as observed on a defect free polished CZ wafer.

Rapid thermal annealing (RTA) can be applied to dissolve small defects such as voids or small-sized oxygen precipitates and to manipulate vacancies in a specific depth from the surface. This can be achieved at elevated temperatures around 1300 C and via NH 3 dissociation at the surface at temperatures >1150 C. In an earlier study (Araki et al., 2013), it had been demonstrated already that even under oxidizing ambient, enhanced bulk micro defects formation around 1300-1350 C can occur. The near-surface region is monitored via its homogeneity of precipitation and in-depth vacancy profiling by Pt-diffusion. Simulations of defect dissolution during RTA processes are performed up to 1290 C under different ambient. The size-dependent defect dissolution behavior is predicted and verified by measurement of the gate oxide integrity.

Herein, the concentration profiles of nitrogen after nitriding rapid thermal annealing (RTA) of Si wafer surfaces are simulated. A model describing the fundamental partial differential equations for diffusion and interaction of nitrogen, vacancies, interstitials, and nitrogen vacancy (NV) complexes is used for this thermal process and the equations are solved simultaneously. In addition, thermal stress tests via intentionally induced stress due to the temperature gradient in an RTA process are conducted. By these wafer strength tests, which apply a controlled stress level, the relative slip robustness of wafers with nitrogen‐indiffused RTA and polished wafers are compared quantitatively.