The effects of RTA processes on flow pattern defects in Czochralski silicon

The changes of flow pattern defects (FPDs), one kind of grown-in defects in CZ-Si, in RTA annealed wafers were investigated in this paper. The wafers were rapid thermal annealed in N₂, N₂/O₂ and Ar atmosphere respectively under RTA processes. A void was found on the apex of the parabola outline of FPDs by AFM and optical microscopy. It´s shown that the hole on the tip of FPDs became shallower in depth and larger in width obviously when annealed above 1100°C, esp. annealed in Ar atmosphere 1200°C. Furthermore, it´s also shown that the density of FPDs to reduce when annealed above 1100°C, and most of FPDs in CZ-Si would disappear during RTA process in Ar atmosphere above 1200°C.