Effect of annealing conditions on the formation of low-dose SIMOX structures implanted at 190 keV

Abstract

The structure of low-dose SIMOX wafers as a function of annealing conditions has been studied using TEM. A set of samples were implanted at 190 keV with doses of 0.5, 0.83 and 1.8 × 1018cm-2 oxygen followed by annealing treatment at different ramp rates (1~ Cmin-1 or 5~ Cmin-1), temperatures (1310 °C or 1350 °C), and holding times (0 or 5 h). The results show that a higher annealing temperature (∼1350 °C) with a longer holding time improves the quality of the top Si layers and the smoothness of the interfaces in low-dose SIMOX wafers. A slow thermal ramp rate results in sharp interfaces but leads to a high density of Si islands in the buried oxide (BOX) layer. Chemical etching experiment performed on the top Si layer of a low-dose SIMOX shows pipeline structure indicating the inhomogeneous chemical reactivity of the top Si layer. © 2001 Kluwer Academic Publishers